Reasons why men follow women and girls into public toilets:
Men will beat them up in the gents.
They have every right to be there
No on can tell
Ok, you can tell, but you can't ask
Some pass, therefore every man should be allowed in
There are no police on the door
Women need a chance to compliment them on their hair.
Someone thought someone was trans, but they weren't.
They are going to do it anyway.