From Infidel753:
Even those businesses which are part of national chains provide goods and services which would otherwise be in short supply in some communities. They employ local people and do some of their spending locally. If those businesses are destroyed or suffer massive losses from looting, in some cases the chains may decide it’s not worth re-opening in the same area, damaging the local economy. In the case of small locally-owned businesses, some individuals — who, again, had nothing to do with Floyd’s murder at all — have lost everything.
Blocking roads and stopping traffic is, if not violence, harassment aimed at equally innocent people. Those victimized by it who didn’t already have very strong feelings about whatever issue such “protests” are about, are likely to be turned against the perpetrators’ position. Remember, what matters is not how you think people should react, but how they actually will react. Such tactics, like the destruction and looting, foster hostility to the protesters’ cause, not support for it.
That may even be the intent, in some cases. There’s evidence that much of the violence is actually being committed by white supremacists who have infiltrated the protests. Videos have shown masked white men committing vandalism while ignoring black protesters who were trying to stop them. Infiltrating provocateurs into protest movements to foment violence and thus discredit the protests is an old tactic, and there’s a subset of white supremacists who advocate bringing about chaos and anarchy in the belief that their cause would eventually win out under such conditions.