Like with "demons".

If the demons are very intelligent, they might have a reason to be the way they are.

If they can't help being evil, I'd consider them someone with a natural disorder; they can't help being the way they are. Maybe we can't be on friendly terms, but I can at least try to draw some boundaries, and only when those boundaries are continually crossed would I totally distance myself from such a being.

I have some experience with finding demons aren't all they seem, really -- or at least en entity that identifies as a demon. Also many that used to, and then found their true forms outside of their self-hate.