Can you have the moral high ground if you're using violence against your people?

well if they turn out out to be violence and can be destructive (they called riot), yes they can

I don't think so. If the authorities are willing to point something that permanently damages hearing at thousands of people in the name of "crowd control" or "protecting property" then they don't deserve to be the authorities anymore.

In the grand scheme of things, property just isn't that important.

Also, did you watch the video? They were just standing there.

> If the authorities are willing to point something that permanently damages hearing at thousands of people in the name of "crowd control" or "protecting property" then they don't deserve to be the authorities anymore

There are absolutely riots where deploying such a weapon would be justified. On one hand, you have loss of hearing. On the other hand, you have the possibility of loss of life. It has to come from the perspective of protecting the people, including those who are rioting, which is a difficult judgement call to make in any case.

Which means some undercover cops throw a few stones whenever they want it to be a riot.