I think people draw a distinction, valid or not, between "looking for similar people" and "excluding different people." The former is seen as more acceptable.

I think people draw a distinction, valid or not, between "looking for similar people" and "excluding different people." The former is seen as more acceptable. For a group that is a small percentage of the population, a niche dating site is acceptable because it helps them find other people in that group. For a group that is a large percentage of the population, any generic dating site will help them find other people in the same group, so a niche site only makes sense as a tool of exclusion.