Do the police not check before the event area if they think weapons are stashed. It seems like many are looking the other way, probably due to leftist orders. If they did not want clashes they would not allow non-permitted people in such numbers. I am not a neo nazi supporter at all, they are just white supremacist leftist totalitarians and about the mirror of black lives matter.
A few decades ago antagonistic protesting groups were never allowed to get anywhere near each other.
In VA, they were intentionally marched into each other. The violence was not prevented it was facilitated. Violence appears to be precisely what the (D) Mayor and Governor wanted.