This sort of thing is very much going to be one of those incomprehensible cultural artefacts that people in a future society look back on and wonder what on earth was going on.
And, yes, EdgeOfACoin, that was very much my thought too. It's blindingly obvious that this is not a group of males.
TRAs occasionally like to play the game "well, if you let transmen into women's spaces, then what if a man decides to pose as a transman!?!?"
If you put almost any man into that photo, it would be blindingly obvious he didn't fit. Very few men could pass as transmen, whereas any man could pass as a transwoman.