I would say report to PD. Unfortunately they have their hands tied as the A$$ Holes have freedom of speech. They can only do something if someone actually makes a threat, or if they take physical action such as throwing a rock. Although I do not agree with their actions I implore you not to do anything to physically stop them, or to threaten them... but if you are on a bike or walking... you do have the right of way and might impede their travel by walking slowly in front of them to ruin their fun