Based on what I read in Second Darkness, Drow are regarded as dangerous and irredeemably evil monsters. Infact in that campaign setting little is know about Drow at all, most people don't even believe they exsist outside of stories. What little is know about them is that they kidnap innocent people and take them underground never to be seen again.
I that case, I would say that killing a Drow on sight in Golarian is no more evil than killing a White Walker on sight would be in GoT.