Revolutions always seek to make things worse and worse, just before the entire society implodes. This is what they are accomplishing by targeting the police and firefighters. Prepare, people: war is coming to our own soil.
Sometimes communist revolutionaries misjudge their moment and in the backlash they are crushed.
This happened in Indonesia in 65-66, and it led to the massacre of a half-million of the communists and others.