There is some confusion on these. One has to do with identity, the other has to do with sexual partner choice. I.e. I was born a man, I feel like a woman. In an unrelated (to identity) note, I prefer X-Y-Z as my sexual partner.
The conservative/conservatism bit has to do with the hypocrisy that man, woman should be the only available choices of gender, and that "man + woman" should be the only allowed sexual partnership. I will not bring religion to the discussion, it only makes things shittier.
This (imho) is the founding stone of fascism, you are different than me (postpartum gender change not allowed), and your choices are different than mine (man + woman, and no other combo allowed).
When a company suppresses and eventually kicks out these communities, they may be doing it for the $$$$, but in the end of the day they ostracize people only because of their identity and choices. As for the “stupid automated moderating..” I call bullcrap. It is a mix of hate and incompetency. But driven by hate and conservatism.
If Tumblr wanted, they could have created an tagging mechanism that could facilitate people to find their own groups/fandoms.