fauxtestor
A fake protestor; someone who is probably there because they are being paid.

They are usually violent or attempt to incite violence.

They don't actually care about any particular causes. Virtue signalling is more important to them than offering solutions.
Did you see those fauxtestors at the Trump rally yesterday? Soros paid them to be there. All they did was curse at people, spit on them and then played the victim when someone stood their ground.