Yet, they are still "Evil". Just because something's "Human" doesn't make it not evil. Daedra are the monsterous, pure essence of everything wrong with people.
Molag Baal is easily the worst, followed by Mephala and Boethia in no particular order (... Aren't those the three revered by the Dunmer?)
Hircine, Dagon, and Sheogorath are also evil, though not quite to the same extent as the above three due to qualities that mitigate their "scourges".
Namira and Malacath are evil to everyone that lie outside their selected demographic, but great to their followers - Very Homicidal Lobbyists, in essence.
Azura seems to be the opposite of the above: Neutral or benefical to most, but a complete [censored] to those who decide to worship and honor her (Look at the Dunmer)
Peryite is villainous, but doesn't become quite evil because he's so incompetant. (I think that's his "real" sphere, rather than "order, pestilence, etc"...)
I'm not sure what Meridia is.
For something to be evil, it needs to be able to come from the same reference point as humanity.
The Et'Ada are far bigger than mortality and their actions cannot be described as good or evil.
It does not fit their frame of reference, since they do not belong to a mortal society, they are not on the same
level and you cannot judge them as you would a neighbour.
They can be described as (seemingly) beneficial or destructive.
Molag Bal is right through might, domination and defilement. He is not evil, though mortals that go outside of the bounds of society to pursue their own desires alone may be described as such.
His sphere may encompass positive outcomes, such as Vehk showed by reaching heaven through violence. Taking the divinity the gods will not share, for love of his people.
Dagon is change through destruction. He can no more be described as evil as an earthquake can.
Sometimes the stagnant needs to be eradicated for a new path to bloom.
Hircine is the hunter, he is a basic trait of humanity, prosperity through skill.
Hircine does not just hunt, whenever a goal is relentlessly pursued, that is Hircine.
Sheogorath is madness, but madness can be kind, a blessing. Madness can keep the horrible facts of reality at bay.
Madness is essential to the arts and philosophy. The jester has its place by showing the wise a funhouse mirror version of themselves.
Namira's sphere is obscured to mortals. She is unknown and unknowable, inconceivable. A concept that does not fit inside a human mind.
The unknown dark may be terrifying, but hardly evil.
Malacath is honor through pride. He is the outcast, the ostracized, the defiled.
Malacath shows that there can be strength outside of accepted society and that not to belong does not mean having to give up.
Azura is the Prince of Dawn and Dusk. Like the other Daedra she is not evil in itself, though she is seemingly vainglorious, petty and vengeful.
The mistress of the half-light is good at seeming.
Peryite is the cleansing fever. Purification through fire and ordeal. Order, all things in their place and at their time.
Meridia is the wayward Solar daughter. Banished from Aetherius for consorting with illicit spirits. She has built herself the Oblivion realm of the coloured rooms, presumingly a pale reflection of her former home. She hates the undead with a passion, possibly because of those illicit spirits.
Her sphere is life, and fall from grace.
Then there is Jyggalag, who is order. But other than Peryite he is a cold, clinical, efficient order.
Where Peryite is fluid, organic, alive, Jyggalag is sterile, uncaring.
Clavicus Vile is power through pact. He comes closest to a western view of the devil, collecting souls in exchange for favours.
Im sure Im missing out some, like the Aedra and Ebonheart but you get the idea.
All of these concepts and notions have their place in a society, and none of them are good or evil in and of themselves.
How the concepts are applied by mortals is what makes it ultimately moral or amoral, judged by the framework of their own society.