Don't buy into the free speech attack bs. Only the government can violate free speech. Some ideas shouldn't be given a platform by the public even though they have The right to say it with out getting arrested.People who resort to violence should be prosecuted, whether of the right or the left. It is especially important to do this when free speech is at stake, because free speech is a cornerstone right -- almost all other rights depend on it.
As for condemning such violence, that's routinely done by prominent leftists. Prominent leftists like Amy Goodman or Thom Hartman are not to be confused with center right people Barack Obama or Hilary Clinton, who are left only in the self-interested imaginings of the right.