I'd say both.
I was held back by a group of boys on the school playground at the end of the school day, pinned down onto my hand and knees and the ring leader pulled my pants down.
I was 7. It was the 1980s.
Fortunately DM came down to see why I was late and caught him and made dire threats to him. He was certainly very cagey when our dog was brought to the school gates after that.
But safeguarding wasn't a thing on the radar then. We were about 8 years away from Dunblane occuring and beginning to put controls against adult abuse on to the radar. Corporal punishment in state schools had only been banned a couple of years earlier and was still legal in the private sector.
What is worse now is the avaliability of porn and misogenistic culture. It's not tatty magazines in hedges or grainy VHSs. An unregulated phone/ tablet/ computer can share content fast.
As a parent who tries to be responsible, has controls and monitors what my sons do, I hope that they haven't been exposed to these cultures. I haven't seen evidence that they engage with them, but my 14yo is far more technically minded than me so there are limits on what I can manage. Both are still very "eurgh" to things like kissing and I hope that's a healthy sign. They do have healthy real life interests and favour the company of sensible, calm people. I talk to them about boundaries and they have come to me if they have been uncertain about online content (which have been minor issues)
But there are no guarentees.
Posters are raising church schools and leafy areas. I suspect that they will contain a greater proportion of parents with these issues on their radar and confidence at the process of reporting them when they occur. Many parents will have safeguarding training from professional or voluntary roles. I doubt that there are major differences from one school demographic to another in terms of incidents being likely to occur and it's a reporting difference. I wouldn't assume that any school is free of it, but individual schools may be better at promoting healthier cultures than others.