Police brutality and other forms of suppression attract attention he doesn't want and could easily avoid. Now the situation is more volatile.
These aren't just trolls we're talking about either. As shown by the demonstrations around the world, significant numbers of people are attached to their democratic ideals. Hick was elected. If people feel he's shutting them out of their democracy, he's just bottling bad energy. If he was truly concerned about "being blamed" for something bad happening to the protesters, then he wouldn't shut down the structures of protest, both in the park and online.