There's flaws with the whole D&D morality system itself. I'll post more on that once I've powernapped. For now I'll say there's this little thing called "reasons" and "context". Why people do "evil" things. yet may be "loyal" for example.
Anyone else remember that evil dwarf in Throne of Bhaal in BG2? You can play as a good none judgemental character (or any alignment really). And he'll quickly stick an axe in you if you claim the moral high ground (at least that's what he implies). But if you simply coexist" you'll have a little moment just before the final boss where he starts to become just a tiny bit sentimental.
The drow from BG2 is also another good example. And Sarevok from the Throne of Bhaal expansion. Not "Evil" for the sake of it, but "complex". Driven. "Action and reaction".