I wonder if racists get friend suggestions for people who aren't their "race" in appearance terms; I'm imagining that could be an emergent selection not explicitly encoded for. If that were the case ... would it be so different to people making that selection. It's a question of allowance vs. instigation I suppose ... but if you knew that behaviour was likely to emerge then the line gets blurred somewhat ...
Rarely. I operate several facebook profiles that exclusively look at very racist or politically extreme people, and guess who FB keeps recommending as potential friends.