Do they? Really? I'm not saying it doesn't happen but it's not exactly 'common' is it?
It's more common than it should be. I'm 39 and just last week had a car full of middle aged men pull up where I was waiting to cross and ask me to suck their dicks. Husband and teenage daughter saw and hear the whole thing and it was totally humiliating. One of many many many instances I've had since 11.
First time I remember it was when I was about five and a car full of men stopped as my Mum (23 at the time) was picking up my teddy I'd dropped and said she's clearly gagging for it because she bent over in public. I knew then she was scared and because she said to ignore them to me, and when I heard her friends complain about the same type of stuff it felt like it was just a normal thing men did.
When I was 18 I had a man garb me towards him in the street and grope my breasts and try to get his hands down my jeans (thank fuck fashion at time tightly belted jeans with baggy jumpers tucked in because he'd have been inside my knickers otherwise. College (the place it happened) and my own mum told me to not make a fuss so I just stfu about it and didn't make a fuss when similar incidents happened too
I can say my Dh would challenge men doing this and he does now but hasn't always. In his late teens and early twenties he didn't challenge his mates catcalling women as they walked past the beer garden. He didn't challenge his mates trying to lift girls skirts up at school etc and he feels horrible about it now. Nothings he thought were "banter" he now is ashamed by and I think that's what makes him challenge things now.
He had no idea what I'd put up with over the years because it didn't happen when he was next to me, until one time he about five mins behind me walking home because a friend held him up and dd (4) at the time was upset and tired. He saw a car full of men slow driving next to me and making sexual comments. He asked why I didn't tell them to fuck off and just kept walking like they weren't there.
Had a very very very long chat about why, and he gets it.
There's been many times since where Dh has caught men harassing me when they've thought I was alone, never once has anyone other than him intervened so while I know I believe when he says he would and does now call out men for this stuff, other men haven't helped me and have either turned the other way or been mates with the cunt harassing me and laughing or watching him grab me etc.
One of the worse cases was when I was pregnant with dd, we were going out for a meal and Dh needed toilet when we got to pub, so I went to bar for (soft) drinks, man started asking me to go sit with his mates and wouldn't take no for an answer, dozens of men and two bouncers watching him grab at me to pull me towards him and did fuck all, I asked him to leave me alone and he punched me in the face just as Dh was was coming back from the toilets, Dh grabbed the man and pulled him away from me, pervs mates then came over to defend him and THEN the bouncers came over to stop Dh hitting him. They asked us to leave despite me having a bust lip from the punch and then seeing the whole fucking thing.
So while I can say my DH would challenge these men, he dislike men who get offended and jump in with Not All Men and there's been a family row when he's called out men in my family for disgusting attitudes towards women, I've been in enough situations to know my experience doesn't tally with "most men intervening" and that of women I know.
I'm older and way more confident now and will report and challenge every shitty attitude and I've noticed that men who moan "not all men" usually do a milder version of the behaviour being complained about and don't count themselves as pervs. Every man in real life who've said this to me have been very sexist men to start with.
Decent, kind, understanding men don't get angry and try to derail conversations about male sexual violence with Not All Men.