First off, nothing was destroyed or even significantly damaged so far.

Secondly, targeting individuals carries a much higher risk of civil litigation, potentially bankrupting the individual protestors for life. It is understandable that people don’t really want to risk that. And it is also much less effective if your main goal is to incite media coverage to keep the topic in the public debate (as it is otherwise easily drowned out by what ever is the latest media freak-out incited by pundits like Trump that play a similar game).