That all they are doing is increasing his level of support? This latest one where people, on American soil are waving Mexican flags and causing violence is playing right into his hands. Take a voter who may not like Trump, or Hillary, but will vote for someone. And then they see these protests about what Trump has been talking about and they decide to support him. It seems every time something like this happens, his polling number go up. The best thing for these protestors to do would be to completely ignore him. But instead they antagonize him, so he responds forcefully and the more he responds, the higher his numbers go.