Which bathroom should these guys use then?
Anyway, in regards to the OP, disgusting behavior. It's not okay, and I find it sad/funny/predicatible that people on here by won't believe it. I know a lot of trans people, as well as very masculine women and have been there when they have recieved tuts and stares. Not that much of a leap.
I've also been the recipient of harassment and abuse when the girls at school found out I was bisexual and believed I was 'staring' at them changing. I'd never want anyone to feel the way i did. Regarding me as a threat despite the fact i was just trying to live my life.
It's also true that TW and TM have been using the bathroom they're most comfortable with for yonks. My actually-genuinely-middle aged family friend is a TW and as a condition of getting a GRC, had to 'live as a woman'. That includes using appropriate bathrooms.
How about we just leave people the hell alone when they're trying to pee? If they stare, make comments, etc then find the appropriate security or phone the police. Harassment has always been illegal and that won't change.