JRPGs are games like Final Fantasy. Many here dislike them simply because Bethesda RPGs are worlds apart from JRPGs, therefore the denizens of this forum typically have drastically different tastes.
I think you have explained the reason.
Japan has different culture from the west, and as a result, the tastes of people there might differ from the tastes of people in America or Europe, which will be reflected in their video games and other aspects of popular culture, and generally speaking, most Japanese video games are designed to appeal to Japanese audiences first, and foremost, which works well for Japanese audiences, but then when they get imported to the west, this can cause some problems, as while certainly some like them, obviously enough to make importing at least the popular ones like Final Fantasy a worthwhile endeavor, but there will also be those who, having mostly played western RPGs, will find many aspects of the games originating from a vastly different culture to be not to their tastes, and therefore, they won't like them. Since most members of these boards population are from places in North America or Europe, they percentage of people who do not like Japanese RPGs would likely be much larger than if you visited a Japanese website.
Of course, this is my own speculation on the matter. Since I'm not Japanese, and don't live in Japan, for all I know, Japanese gamers might hate Japanese RPGs, but I find that unlikely as they probably wouldn't make the they way they do if the people of their own country didn't like them. And since I don't choose what games to play based on what country made them, I might not necessarily be able to relate to the notion of resenting games of a specific type from any country. But from looking at the reasons for not liking Japanese RPGs usually sited by those who do not, it sounds like it all really boils down to a difference of taste (Than again, when it comes to not liking any form of entertainment, so long as it's not so bad as to not have any fanbase, it usually comes down to a matter of taste.) which probably stems from different cultures and being used to different things in games.
Edit: As far as voice acting: both western rpg's and jrpg's have some terrible voice acting
Very true.
In fact, voice acting that is, at best, mediocre is pretty common in video games. But regardless, it's really not fair to judge the voice acting of Japanese games if you go by the English version, unless the voice acting in that version is the same as in the Japanese version, like for games like Resident Evil or Silent Hill which use English voice acting even in the original versions, because then, the problem isn't with the original game, but with the translated version, so the fault lies on whoever was responsible for the English voice track, not the original Japanese one, unless the Japanese one was bad too, of course, but if you just go by the English version, you wouldn't know if that's the case. And really, I've come to expect that, with some exceptions, if a video game, movie, or any other medium that features spoken dialog is translated into a language other than the original and has new voice acting dubbed in for the translated version, the voice acting is almost always terrible. It's why is usually only watch anime with subtitles, and in fact watch any foreign production this way even if I could watch it with voice acting in a language I understand.
Now, you could criticize the translated version for bad voice acting, but if you want to criticize the game, as it was originally designed for its voice acting, or indeed Japanese RPGs as a whole, for that matter, you have to go by the original Japanese version, I would say.
Final Fantasy VII is the reason why I can't stand JRPGs. I've explained at length multiple time why that game was the worst game I've ever played... so suffice it to say that because of FF-VII, I'll never play another JRPG
So basically you hate every single game of a specific genre from a specific country because you played one game in that genre that you didn't like? That seems like a odd choice. It would be like if I decided to hate American science fiction movies because of the Star Wars prequels.
though the truly god awful acting and completely ridiculous plots in many FF games also puts me off. From what I've seen of FF8 and 10, I can't fathom why anyone actually likes those games.
To be fair, from what I've seen of those games, I can't see why anyone would praise their plots either, and if they are overall good representations of what the stories of most Final Fantasy games are like, I can't see why anyone would like those stories, but if the gameplay is good, I honestly don't care too much about the story. Sure, if I can get a good story to go along with good gameplay, it's great, but I don't need an exceptionally good story to enjoy a game, I play games for the gameplay, if I'm looking for a story, I'd read a novel, and I do read novels, they're a great means of storytelling, and that's why I turn to them when I want a good story. For a video game, as long as the story doesn't have any overly glaring plot holes (After all, if you're going to bother to have a story in your game, it's a good idea to make it so that it doesn't leave me scratching my head and wondering what the hell just happened, though some Final Fantasy games might be guilty of this.) and serves to explain why I'm doing what I must do in the game, it's good enough to work.
But after all that, I suppose I shall offer my own thoughts on Japanese RPGs. To be honest, I don't usually play many of them, I don't hate them, in fact, if enough people like them to ensure that games like Final Fantasy can continue to to be successful, I figure that they're doing they're job as an entertainment medium, and thus their existence has as much merit as their western counterparts, I just don't play many of them personally, I do play a lot of Japanese games, I don't discriminate based on place of origin in games, if a game appeals to me, I'll play it, regardless of where it comes from, it's just that the stereotypical Japanese RPG, by which I mean games like Final Fantasy, just doesn't appeal that much to me. The character designs usually aren't what turns me away, since I watch a fair amount of anime, I've grown used to spiky, unnaturally colored hair and big eyes often associated with Japanese artwork (Although even so some games still take it further than I'm comfortable with, I look unto Final Fantasy 10, looking at some of the characters from that game, I get the impression that they just recycled designs that were rejected for previous Final Fantasy games.) and I could also very easily complain about the stylistic choices of western RPGs too, I'm talking about huge, spiky armor on man, and women with chainmail bikinis, and knights and elves and a world that in general looks like a romanticized version of Medieval Europe with mythical creatures thrown in for the hell of it, at least in Japanese RPGs, the designs usually feel more original, though that might also be because they're a little less familiar to me, it's not the underaged heroes either, for the same reasons I stated above, it's not even the huge swords. Oversized swords don't bother me that much, although I prefer it when the character wielding them actually looks like someone who I could imagine being able to lift such a large weapon, and really, it's not like American RPGs don't have their own absurd equipment designs, once again, I must bring up the chainmail bikinis, it's not even the stories, I mean, I've already given my thoughts on the importance of a good story in a video game, and it's not like western RPGs don't also often suffer from bad stories. Let's just face it, most video game stories aren't all that great, no matter where they come from, there are exceptions, of course, but as a whole, the potential of video games as a story telling medium has not really been used so well. In the end, the main reason I don't play many Japanese RPGs because of gameplay, more often then not, they just don't have the things I look for in an RPG. Usually they don't seem to offer much choice in terms of character customization or how you develop your character, usually you're forced to play with a specific, pre-defined protagonist, while some western RPGs I play are like that too (Although I don't really approve of the practice, I can live with it if the game makes up for it in other ways.) they often still give you a fair amount of options in how to play that character, offering various skills that help to define your character's abilities, and in games like the Witcher, while you can't choose who you play as, you'll still encounter choices during the course of the game which will effect the game experience, so while you can't change the appearance of your character, you'll still be able to change other aspects of the experience through your choices, by comparison, looking at Japanese RPGs, they often don't seem to offer this, which might be fine if they made up for it with other aspects of gameplay, but all too often, it doesn't look like they do to me, certainly, they don't seem to do combat or any of those other things that RPGs always have better than games that focus on them, so I have no reason to play them for that either. So I don't play them, but if other people do, good for them, they should play whatever games they like, and I doubt most people play games they actually don't like, I know I don't. If I decide I don't like a game, I stop playing it. Unless I concluded I won't like it before even trying it in which case I never bother to start, but people can play whatever games they like, even if I happen to think those games are boring and don't see where the appeal is.