?. in trying to answer the OP....
I guess it comes down to what 'noise' do you expect me to make?
I'm not on Twitter and there's little chance of me signing up just to tell some lowlife he's a lowlife.
I'd hope and expect men with a profile in football would speak out in that instance in addition to him being suspended and condemed in the press. If I was asked my opinion ( which nobody has ) I?d say I found it disgusting.
For me personally I'm pretty selective about where I go and who my friends are. So whilst I would ( in most circumstance ) pick someone up on a sexist / racist / homophobic attitude or comment, I don't come across it very much in or outside of work because most everyone I work with or socialize with are decent people.
If anyone made sexist comments where I work they'd be in front of HR pretty quickly. Any kind of physical assault and they'd likely be dismissed if not arrested.
On an aside, I also think contrary to some comments, being a man and challenging some random bloke?s sexist remarks doesn't reduce the chance of experiencing violence at their hands.
I'd certainly think twice before approaching some group of burly shaven headed sexists in an east end pub with my Surrey accent to tell them to modify their thinking. I'd expect to get thumped.
All the blokes I know who've stepped in to help a woman being attacked in the street by their partner ( which I hope I'd have the balls to do ) have been attacked unsurprisingly. In two cases by the warring couple together.
The reason, to answer another bit of your OP, I personally don't often get involved in these discussions on MN is partly because frankly as a man one tends to get accused of being the problem if you don't agree entirely with the party line. I find some peoples attitude towards men in these threads to be, ironically, sexist and offensive So I tend not to get involved.
Doesn't mean I don't find rape and DV abhorrent, probably leaves me less informed though.