If you're making someone do something by force then what they do can't be defined as moral. It would be compliance with someone else's wishes, not obedience to an internal directive. Therefore moral matters are for one's own consideration and not something to beat other people into submission with.

Somebody else here, I think an issue might be that it's people being under (presumably) immoral oppression lashing out with immoral means, so to try to stop them might itself be siding with the also immoral oppression. There's something here about the goal and the means.