Are you asking sincerely, or are you trying to do some false equivalence sealioning nonsense?
It seemed like a legitimate question. The parent comment said pretty much every selectivity group is okay except for white males and the child post simply asked why is that the case. At least that's how I read it.
My point is that I find it extremely hard to believe that anybody could ask the question "what's wrong with a whites only event?" in sincerity.
That said, I admit that a men only event is reasonable in certain circumstances.