No, you can't, not if you advocate for the use of rational thought rather than emotional appeal... or maybe you can produce a philosophical principle that doesn't induct the other classes, but I have my doubts. So go for it: present the philosophical basis for this claim that doesn't induct the other cases.
Sexual harassment/abuse is a violation of a basic human right that also serves no higher purpose. Since men tend to perpetrate most of the sexual harassment/abuse, they should speak out against this violation of a basic human right.
Terrorism is also a violation of a basic human right, but sometimes terrorism serves some higher purpose (i.e. freedom fighters are usually terrorists to their opponents). Muslims may not wish to speak out against Islamic terrorism when that terrorism serves a higher purpose in their view.
The 2nd argument has absolutely nothing to do with the 1st.
In my view, your position is unnecessarily narrow in its scope.
You have provided nothing to establish why, just because (some men) perpetrate abuse that (men in particular) have a duty to fight it. You have presented a non-sequitur. Good job. Try again.
Hang on. Hadn't we broadly agreed that men
should denounce abuse perpetrated by men? Now I'm confused.
Actually, I was just about to ask you about this. Well, specifically about the degrees of ought that are involved. I am fairly clear and happy with what I will call, 'the rule' raised here (about the moderate non-offending majority denouncing the offending minority in their group). I agree that by and large (I'm sure there are exceptions as there are with most things) this is a 'good' rule.
It's when it comes to the non-offending majority being held accountable for, being seen as responsible for and as a consequence being expected to apologise for the attitudes and actions of an offending group minority that I find myself flip-flopping. One minute I agree with it and the next I don't.
To analogise, and hey let's use muslims as an analogy again, Christoper Hitchins, among others, was, I believe, of the opinion (and many atheists agreed with him) that moderate muslims provide cover for islamic extremists. He was therefore clearly of the view that the moderate majority were to some extent accountable/responsible for the actions of the offending minority in their 'group' (muslims). I was always dubious about this view, even though I heard it promoted quite regularly at various secular/atheist internet sites. And, to be honest, I don't think my reservations derive from any tiptoeing around muslims, or theists generally. It just struck me as awry.
So, I'm wondering if it similarly awry to extend 'oughts' in the case of men beyond merely saying 'it would be helpful if you did decry (and perhaps step up and fight) the offenders in your group' to 'you should do these things because you are in some way responsible'.
Don't get me wrong. I'm not suggesting that when it is said that men should denounce such things, it is necessarily or always implied that they should do it because they are in some way responsible. But the words 'apologise' and 'responsibility' have at least gotten a mention here and I'm just interested to explore, not least because I flip flop.
PS LD. Good point. I personally think we could add your observation about higher purpose to the one about underdogs*. And I suppose they are not unrelated. And in fact both may be related to the idea that sympathies come into play for all 'sides' (as in
'I won't be too hard on the moderates in group X, of which I am not a member, who don't denounce the offenders in their own group, because I sympathise with the plight of group X generally' and
'I won't be too hard on the offenders in group X, of which I am a member, because I sympathise with their cause even if not their methods')
* And prevalence.