The purpose of carrying weapons is to potentially use them. It is also a nazi-like bullying tactic to scare people who don't agree with them. The thugs who are carrying weapons to political rallies are not advancing any political aims by doing this but are turning off people who would have listened at least to what they had to say.

The right to bear arms publicly is not in the Constitution. It's a misreading of the Second Amendment and someone's going to get shot.