If protesters have a permit for their protest, obey the orders of the attendant officers, and are non-violent, then no. However, if the protest becomes violent and/or the protesters refuse to follow the orders of the on-scene police and crowd control is required I have no problem with dogs being turned loose if necessary.
Lets see, if you have ever heard of the No Dapl movement. The pipeline organization hired mercenaries to taze, beat or order their dogs to attack. The protesters were only praying and were armed with prayer. Why would they do that to such peaceful people. And concussion grenades, now that is too far. Someone has lost an arm because of that and my cousin is dead because of the DAPL's violence. So I say that dogs should not be unleashed on dogs. Most of you guys are really ignorant. That is very funny to see how stupidly confident you are in your so called 'leader'. He said he was going to build a wall in the first one hundred days. Well guess what, he hasn't done it. He used all those funds on either his company or for the military after he specifically stated that he was going to 'use' it to 'build' a so called 'wall'.
According to the constitution people have the right to peacefully protest and unleashing dog on protesters is an attack on the constitution which is the foundation of this country. So if you believe it is ok to unleash dogs on protester then you do not believe in the constitution so there.