My view is this.

As a duergar, I am free to get whatever help I can out of the goods in my cabal. I might hate the elf, but that doesn't mean I shouldn't travel with him, and use him.

As an elf, I should not be travelling with the duergar. It is my responsibility to refuse to endorse his way of life.

That said, as my last char (Hammond), I did clash with cabalmates for alignment reasons. One example being the withholding of the Justiciar's con quest item because it was obtained by the murder of an innocent man that abided by the law. But what if that fire giant is always being so damn nice to you? Taking Baalshiwaax or whatever his name is as an example, I was reluctant to use my spells on him. Then when he didn't trust me (despite having said he did), I was angry and mistrustful, withholding my spells for a bit. However, he was just so damn nice all the time. In the end I found it hard to find a justifiable reason to be against him, especially as a human raised to judge actions.

Wouldn't my character therefore start to see him as not being evil? I'm not sure it would have been such bad rp on my part if this had happened. Nor on his, for that matter, since I can't see why an evil wouldn't such up to someone useful to him, like a transmuter.