The argument is not whether in that instance the speech is harmful -- it surely is. The argument is whether we tolerate that harm vs allowing bureaucrats to use that harm to silence dissent. I would punch that guy in the face, and he could sue me, or I could be prosecuted, and when the facts came out, I’d probably be let off with the most lenient sentence for doing so.
But we don’t want the state weighing in on the speech. We as individuals can shame people for bad speech or even get violent, if necessary, but the government MUST stay out of it for society to be livable.