It may not be personal to your lovely son isadora (who I am sure is lovely) but other rapists and abusers were somebody's son. I'm sure if you think about it you can think of (at least) one man you have met that you wouldn't have felt safe or comfortable changing/ peeing/ sleeping next to or just being in the same room as.
It isn't all men, lots of men are lovely and kind and gentle. But it could be any strange man. And sometimes it is men we know :(
I agree that there is that often unconscious ease that you can feel in a single sex toilet or other female space. Even if you aren't escaping from actual violence, just from leers or looks or comments,. Or sexist remarks or attitudes. Just plain old healthy sexual tension even!!
It is one thing being amongst male and female friends, family or acquaintances, but being out amongst public/strangers, particularly in quite male dominated environments, is sometimes just subtly draining.
If I was leered at by a lesbian whilst changing I'd be massively pissed off and probably say something as I would (unconsciously) fancy my chances even if she became violent aggressive - but would I challenge a man who was leering? Not unless I was in public. And only then because I am sometimes a foolish fiesty so and so who forgets how strong men are. Many other times I'd just feel afraid.