That's exactly why no one should give a shit, they'd all end up looking the same under the armor and becoming genetically modified 800 pound slabs of meat anyway. They aren't in the lore, that's the end of it. The trannies however wont go the fuck away, and the few real women who do play 40k don't want female space marines either and they didn't buy them when they existed in the 80s(hence they were discontinued fairly quickly with that era of lore basically being a mess that isn't even remotely considered canon).