Hold on Pela. I'd like to get a few things clear and see that we're on the same page. In advance; I don't mean to sound condescending, I'm trying to clarify things.
(1) Firstly, a pretty important distinction, are you under the impression that I am debating that morality and goodness are the judgments of certain people at certain times? Because I'd like to make it clear that I'm not. Well, here and now at least. I merely think that we can become concordant that, for example we both think that Dagon is evil (unlikely). Or, as you said to begin with, you think evil is something we all are a little bit of, and since Daedric Princes hold spheres that are particular aspects of people, it makes sense some would be evil...unless to cut it short...you think that Daedric Princes are all enough of the positive and negative traits that they balance?
Next, I entirely disagree about trade. PM me if you'd like, or make a "Daedric Princes, the Real World, and What Is Evil" thread and invite me and I'll be more than happy to debate it. Or we can return to it later in the thread.
(2a) Next, the reason I listed all these... and bear in mind that I pretty much flat out said I'm unsure what taboos hold across cultures and that you'd likely know more than I (History versus economics major, go figure) was to ask if something was universally condemned across cultures, would you consider that evil, and after brief discussion the prevalent element was things that violate our trust (or social contract).
Thus why I asked if that meant that things that did so were evil, and you're response, as best I can gather, is that society is not necessarily good and that actions have complex motivations, which is true and none of which I debate.
(2b) However, I think the Daedric Princes violate the spirit of what you are saying. They personify the element of, as I said, the Macbeth style murder of the King for personal gain. Or, to invoke Dagon (and some OP relevance!) if you're planning on killing your king, or advocating some change, you're not being terribly Dagonic, if you're planning on total revolution and bloody transformation, you're hitting the high notes. Do we disagree on this?
(3a)Now, next, you have to realize we are debating in multiple dimensions. The Elder Scrolls is a brilliant and complex world, but it is also entirely fictional, it is useful to examine it in the lens of both real world, and fantasy troupe lenses, as well as the world we interact with in-game. So for an example of why a king might be evil, well, as far as a king is concerned that would be if he placed his personal wellbeing above that, and to the detriment of, of his people. If he wasted money and lives on wars of adventure, or placed a heavy tax burden on the populace to build new palaces despite having them in abundance, or perhaps if he was ignorant and decided to close all the hospitals in his country because he figured that if people were going to die, it was in the lap of fate and so it wasn't worth investing dollars in healthcare. I am sure you understand the theme. There's also a margin of rationality, and for an action to be 'evil' rather than bad judgement it requires an element of extremity.
(3b) Which brings me to a timely question, would you consider Alduin as he is shown in Skyrim evil? How about Miraak or Harkon?
(5a) To return to some in-game material, and to focus on my original point, I think the Daedric Princes are evil because they are extreme. Their spheres are vast, but they often take the extreme and least socially positive aspect. Take Bal's quest in Skyrim, now Logrolf was not a good guy, but you beat him to death, resurrect him and do the same, all so he bows to Bal. I can't see that as anything but evil? What about a few other Daedric Quests?
(5b) Namira's quest, where you lure a man to a cave to be eaten by cannibals. Namira is the Lady of Decay, there's no need for murder and cannibalism. And, yet she takes it on.
(5c) Or Vaermina, who exists almost solely to torment mortals by plaguing them with ceaseless nightmares. Now, we know Daedra have no need of anything from mortals, so necessity is not (and actually, never is) a question that is present to them. It is never necessary for a Daedric Prince to murder someone because they are starving.
Awaiting your reply.
Pretty much right on, as far as Bal-inspired societies go.
I'm not sure if Dagon would lead himself to a particularly cohesive society though, considering his focus on both destruction and ambition, or at the very least a construct by Dagon would be much less stable than one by Bal (where strength and dominion go hand in hand)