Are the people that wrote YMCA gay?

The song itself was written by Henri Belolo, Jacques Morali, Victor Willis for the group Village People. Victor Willis has been married twice, and has not indicated that he is now, nor has ever been gay. At least three of the Village People are gay, but there are two that have claimed to be straight. That leaves one that no one is particularly sure about, but I think it's safe to assume that Village People are half-straight, half-gay.

So, the answer to your question is no, not all of the people who wrote and sang "YMCA" are gay.