The event could be “thousands of women and non-binary folks”. Did all these male-presenting people identify as women or non-binary just to be able to attend this event?

According to their Chief Impact Officer, yes. Apparently they "lied about their gender identity when signing up."

What do you think identity politics is, exactly?

Performative politics centred around identity. White is perfectly happy to pretend that men can be women - until it impacts him.