It's a game, a game is meant to be fun, and it wouldn't be fun if your character died soon after exiting the vault because someone who spent his entire life living in a vault doesn't have the skills needed to survive in a nuclear wasteland. It's the same as how a theoretical physicist can fight his way through an alien invasion and, years later, comes back to become humanity's only hope for liberation from different aliens. Basically, the game needs to make a few breaks from reality for the sake of gameplay.
It's not just games either, lots of works of fiction do things that are not realistic for the sake of the plot, as long as it's not too glaring, though, audiences can usually suspend their disbelief on the matter. And even if it is too extreme, in some works, this can be ignored if it's cool enough. Simply put, it would be better to stop thinking "How can I do that?" so much and just sit back and enjoy the game.
Not everyone has this for the PC. Besides, im complaining about how he all of a sudden knows hot use laser weapons, not a regular gunpowder using gun. Guns in general take common sense to use, but if somebody tossed a laser rifle at me, I would be like "Wtf is this?"
Well, taking a look at a laser rifle in Fallout 3, it doesn't look like using it would be all that different from using a gun. You'd still have to point it at your enemy, and pull the trigger. Now you probably won't be very good with it without more experience, but I don't see why you'd need special knowledge to use it at all. Besides, energy weapons is one skill you can tag at the start, of course, this may in part be simply for gameplay reasons, but if you can tag it, maybe it's because it's possible to get energy weapons training in the vault, although you don't SEE any energy weapons in Vault 101, that does not necessarily indicate that it doesn't keep any stocked. A better question is probably how your character can swim upon exiting the vault, because swimming is something you'd definately need to learn, and I don't see any pools in the vault.
But, at the same time, pre-war soldiers didn't have to maintain them, either. I can see how, then, it would be utterly confusing to a random vault dweller (not even twenty-one yet!) could get confused as to the proper care of one. But, not usage.
The care of such a weapon falls under repair skill, though, and if you don't have a high enough repair skill, you won't be able to keep any weapon in good condition. Because of how the game mechanics function, though, there's probably not much it can do to stop you from repairing energy weapons in particular if you're not good enough.
Which movies are you talking about that have anything to do with this game? By the way, if you dont explain things at all, clearly a person wont know what you are talking about, as games are definately not movies, and the only thing they have in common is entertainment. And most movies I know of that are actually worth a [censored] already have their characters knowledgable in whatever they do.
The entertainment factor is key here, both games and movies need to provide audiences with entertainment. And while they are different in nature, in that games are interactive and entertain players by providing them with a fun gaming experience, whereas movies are not interactive and entertain people by telling an interesting story, scaring them, showing characters performing impressive stunts or shooting people, or through other means that don't require intervention on the viewer's part. In both cases, though, audiences probably won't be too entertained by spending hours watching someone try to familiar himself with something unfamiliar, unless the entire point of your work is to tell the story of how someone learns something new, in order to achieve some goal. And in your post, you seem to have denounced many works of fiction that are widely regarded as classics, as I'm sure anyone could name some highly successful stories which begin with someone relatively unfamiliar with what said character will have to do. In fact, this could be said to have its own merits, since it allows room for character development, and developing characters are generally more interesting than static ones. It also may be assumed to be easier for viewers to relate to characters in a story about a subject they cannot be expected to be too familiar with (say, surviving in a post apocalyptic wasteland.) if the characters come from a background closer to them. In speculative fiction stories, it's also a good oportunity for exposition. If your story is about space travel and you've thought up all these interesting technologies, you can have more experienced characters explain these technologies to newcomers to the field, in the proccess also explaining them to your audiences, although it might still distract from the pacing of the story if executed poorly, it would probably seem less out of place than having a long segment of out of character exposition just thrown in there, or having characters explain things that the characters they are explaining to should already be expected to know.