You can make it illegal and actually a crime. The democratic way to make it one is either make that point democratically elected leaders in a civilized manner or vote against them next election and organize into parties/block to influence policy.

Terrorizing and hold regular people hostage with noise pollution, blockade and disrupt their lives is what revolutionary/terrorist organization would do.

If protestors behave like terrorists and insurgents then sooner or later they will be treated like one.