yeah, that’s a weak reason against violent protests. stronger ones are:

• the violence is often misdirected at people not able to bring change, eg. small businesses or cars.
• the violence exhausts protesters. many of them being crippled or killed by police, until the protests are suppressed by too few motivated protesters being left.

btw cops love violent protests. they get to kill maim and torture more people than usual. it’s what many of them signed up for and look forward to with excitement. sometimes they have off duty cops in plain clothes infiltrating protesters to start the carnage. all it takes is throwing one stone near a collegue with shield and helmet to give him an excuse to go on a rampage against innocent protesters, while the infiltrator sneaks off