Seems more like rules state everyone but cisgender men in the way they worded it. Trans-man would be included since it says anyone under the trans umbrella.

Women only… trans women are women, and transphobic or gender critical talk isn’t allowed. Anyone under the trans umbrella (eg non binary) is welcome

The backflow current from fans is extremely minuscule and extremely unlikely to damage anything from that. There are even tests using a damn leaf blower on the fans and it barely generated any current. Even if it did generate a backflow, diodes on the mobo should prevent it from becoming an issue unless it’s a power so great that it just fries everything, but that’s basically impossible with a fan.

Here’s one such experiment.

https://youtu.be/k9KA-xLLQXo