This is an interesting article on non-violent protest
Why Non-Violent Protests Work | Psychology Today
Lots of things that are relevant to the police actions.
"So, while the protesters might be rioting because they feel they have important needs that aren’t being met (seeking to achieve them via violence, or the threat of it), third parties might come to view the damage inflicted by the protest as being more important or harmful (as they generate a larger, or more legitimate need).
The net result of that violence is now that third parties side against the protesters, rather than with them.
By contrast, a nonviolent protest does not create as large a need on the part of those it targets; it doesn’t destroy property or harm people.
If the protesters have needs they want to see met and they aren’t inflicting costs on others, this can yield more support for the protester’s side.
However, as we have seen, violence against others, even disagreeable others, who are not themselves behaving violently can rally support from third parties, as they might begin to worry that threats to free speech (or other important issues) are more harmful than the opinions and words we find disagreeable (again, hitting someone creates more need than talking does).