Political correctness violated free speech. Yes, it did it through his employer, but the effect on all of is the same.
Does the privately-owned enterprise that pays him have a right to free speech? Should they be forced to lose advertising dollars and face boycotts in order to protect his free speech?
The 1st Amendment restricts government - it has absolutely nothing to do with this situation.
He finally said something stupid enough to chase away his sponsors. There's NOTHING in the 1st amendment that protects people from consequences of stupid speech.