I can only assume that the OP and others who think they are 'absolutely fucking correct' or call people transphobic for not wanting to share a space with a penis, are being deliberately disingenous.
It is NOT HARD TO UNDERSTAND.
Violence against women is a GLOBAL PUBLIC HEALTH ISSUE. Women and girls are raped, assaulted and killed IN THEIR THOUSANDS every week. One THIRD of women will be subjected to some kind of violence in her lifetime from men.
Understandably, in that context, some women are simply not comfortable with sharing intimate spaces with men. You know, the humans with penises. Because men with intent to commit violence don't usually advertise their intentions beforehand, it's been considered safer for decades now that penis does not come into women only spaces. The fact that a small and vocal group is now demanding, not asking, to be let in, a group who have penises, is making a lot of women feeling frightened and uncomfortable.
Can you really, really not grasp this?
Or just easier to show how supercool and progressive you are and call women who express their valid fears transphobic.
Here's a name for anyone who thinks it's ok for men to enter women's spaces; MISOGYNIST.
If you support men with penises being allowed into women only spaces, you are a misogynist. Pure and simple.
Hope that helps.