To paraphrase GK Chesterton, its not that telling men not to rape has been tried and found wanting, it's been found hard and never properly tried.
This is it. ^
If everyone knows, how come it was only a few short years ago that it was a very popular trope absolutely everywhere, that plying a girl with a drink so you could have sex with her, was perfectly acceptable. In fact it was part of any red blooded man's seduction technique.
How come it's only recently that people are beginning to realise that what a woman wears, has got nothing to do with the decision of a man to rape her.
Or that her sexual history is irrelevant.
That her being asleep is not consent.
These are really, really recent ideas. And, it would appear, that many men have missed the memo.
It needs to be hammered home.