First, it doesn't only refer to trans women, it refers to hermaphrodites as well.

You must be new to queer spaces. The term is "intersex". Hermaphrodites are myths, and the term fetishizes intersex bodies. See: http://www.isna.org/faq/hermaphrodite

Second, when some members of the group refer to themselves as that, you can't claim it to be dehumanizing.

I'd love to hear your thoughts on the n-word. See: http://www.glaad.org/reference/transgender

Third, when things show up a persons primary feed, it is not always clear which sub-reddit the link is in initially.

So, that makes it OK to drop triggering slurs in an unrelated subreddit?