Why aren't those flock cameras being destroyed all the time in the US?
In our city people vandalized speed cameras all the time, so eventually government gave up and just banned them in the whole province. I'm not sure they did that because of being vandalized, but at least there was direct actionable push back.
I'd probably think people getting bills for hundreds in the mail is a good catalyst to take action on a speed camera. A camera that is used for serious crimes, not speeding, is not going to be nearly as inflammatory.