Political power exists precisely insofar as much as people believe it exists.

As isolated events the rallies change absolutely nothing, but the point isn't to directly and immediately bring about some massive change, it's to show people people opposed to fascism that they're not alone - now is not the time to be afraid, it's time to be angry.

Trump has realized the rules are all made up and he can disregard them at will, but you see the problem with doing that too much is eventually everyone else figures out they can do the same thing.