Self-segregation is not the same as public-accomodation segregation or affirmative action. I think it’s closer to freedom of association, although I’ll admit the lines get kinda blurry sometimes.
Good luck doing the same thing if you’re white.
Agree with your assessment.
Regardless, there is a double standard. Imagine the outrage if 3 white guys had posted looking for a 4th.
Might not be the same, but the laws make no exception for it besides roommates seeking roommates of the same sex in shared housing.