me looking on any femboy subreddit rule

That's like saying men can use the womens restroom because "whats wrong about opening up these safe spaces". But in reality, they become less safe and/or the original purpose of separation is defeated. r/ feminineboys does not mind trans folks at all, because they may have very similar experiences and questions. It doesn't defeat the purpose of the subreddit, which is to help each other understand our femininity. When you go there, you expect to see femboy related questions, not questions asked by femboys. That's like going to a community for european sports and expecting european redditors. No, that's wrong, it's about the topic, not the people. But in a selfie subreddit the posts are the active users themselves. So in this case you expect selfies from the femboy members.

And just check out these women, they literally post on trans or even tr*p subreddits simultaneously..

/r/196 Thread Parent Link - i.redd.it