It can be a fine line, acknowledging our prejudices, and being hurtful. Context and presentation are important. I mean, there are certain things that we arbitrarily key in on with others, attraction-wise. And I can see how some people might be curious about other people's turn-ons and turn-offs, and want to communicate them. But, it's fairly likely to be at least slightly hurtfull to people who match those criteria. Part of the problem may be that these lists mix together perceived character and physical flaws, along with matters of preference and taste. That could make people feel like these tastes are a judgement on them. Case in point, with that red hair example, I like dark red hair, but not the orange-red hair. That's a statement about myself, not about anyone with those colors of hair. Although, I'm not sure if that's what others feel.