Every society has their view of what evil is and considering that undeads in game are considered as different society then it is normal that they will have different views on world around them. Not to mention that they are not seen well from rest of the society, on the stream when Swen revealed that he is undead to the first character (undead started in totally bandaged like coat-hood.. ) the guy attacked him, first character he meets in game. And also when he was starting game with undead there popped warning like window that said "are you sure wanna play with undead if this is first time playing we advise to play with some other char" (something like that)
But in general we all are just guessing on lore and how undead are played. Larian said that there would not be patches until release, so no undeads before release

) but in general we can play undead how we want, we can play them as noble paladins or dark knights or as evil assassins or shadowblades (I go for shadowblades

)