Even as a moral principle, free speech isn't a blank check to express whatever you want without consequences. The founders of free speech principles even acknowledge this with the harm principle, where someone's free speech liberty can be hindered if the expressions cause harm.

I did not claim that free speech should completely unconstrained, and I don't see how such an inference can be drawn from my point above. My point was simply that the scope of the principle that free speech ought to be protected is not bounded by the limits of the first amendment because it is a moral principle that exists prior to codification in law.

You simply stated that free speech as a moral principle wasn't constrained by the law. I was just reminding you that free speech as a moral principle still has constraints, which are relevant to the discussion of expressions that historically harm others (child pornography, Nazism, etc.)