@hightor,
Well, what you call "screaming," I call chanting and there is an important distinction. Chanting slogans is typical at political rallies and there is absolutely nothing about "Build The Wall" or "Lock Her Up" that would incite violence in anyone who is not unhinged or a criminal.
Yes, I do think that without a Trump rally many of those violent, obscenity hurling protestors would have been elsewhere engaging in the same behavior: Likely on a campus somewhere where a conservative speaker was attempting to address an audience.