Dude. I'm just going with what you said.
You started talking about the first amendment in the context of a permitted rally where safety plans were broken by the decisions and instructions of rally leaders. The asshat Nazis and KKK entered the park in opposition to previous plans that would have kept protesters and counter protesters separate. They spread out into the city when the protest was declared unlawful. All who are responsible and accountable for public safety in Charlottesville have said that the violence is entirely due to actions of the White supremacist protesters. END OF STORY.
What other meaning can there be when you invoke the first amendment other than you are claiming the violence was protected speech.
Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the government for a redress of grievances.
By standing "on the side of the first amendment", how else can I interpret what you said other than that you see Nazis and KKK beating black people as some form of peaceable assembly?
I think you should reconsider. You are siding with murderous Nazis and KKK.