"Do not make targeted threads that are abusive or degrading toward another member, group of members, or social group. This includes but is not limited to posts regarding sexuality, race, and religion."
Now I may not be a legal expert, but if we assume Leon had made the thread to target something, it would clearly be the concept of transgender, not any "member, group of members, or social group."
Personally, I think the rule is silly as it is written. After all, we have the mute thread feature for a reason. If someone sees a thread that triggers them, they can always mute the thread.