I think the problem is that we're still stuck on games where saving everyone and everything nets a much better outcome over any other choice and is, therefore, the 'optimal' playthrough. Playing in a way opposite of that (whether or not you want to call it 'evil') is usually just for lols or a noticeable loss in advantages/resources, making it feel more like punishment rather than a valid course of play.
No. It has to do with including conduct that's so morally offensive to your companions that they should be up in arms against you, but they are instead pretty chill about it. Kind of like:
Fenris: I will murder you, disgusting slavers! No one should own a human life.
Hawke: I am going to enslave this elf right in front of you. Suck it.
Fenris: Meh, we can totally still be friends if you give me a Tevinter sword.
Anders: All mages must be free! It is my righteous mission!
Hawke: I'm going to turn all these mages over to a templar who swears to abuse all of them.
Anders: Man, I'm so unhappy with you. Also, we still on for the deep roads? Legit.