The only people required to defend totally "free speech" are representatives of our governments.
The line we probably all agree on when it comes to "free speech," as promulgated in the Bill of Rights is that it stops at crying "Fire!" in a crowded room.
But we make a mistake if we frame the Harvard discussion in terms of re-drawing that line. Harvard is not a governmental body. No organization except a government is required to defend the most offensive manifestations of free speech. I'd be surprised if anyone is making the argument that the offensive posts at the center of the Harvard controversy were actually punishable in some legal way. We can tell the difference. They weren't crying Fire in a crowded theater. But all individuals and their non-governmental associations have the right, indeed, the responsibility to draw lines in very different places. They have a right/responsibility to promulgate the values of civil society. We are headed down a very dark road if our universities can't say "stop", this is not the behavior we condone.