[legalcorrection]

Chaplinsky, the case you quote, has not been used to uphold a conviction in many many decades. The doctrine is dead in practice.

Also, that has nothing to do with making that response with physical violence legal. You can still only use violence when you are defending yourself against physical injury. Sure, provocation might be mitigating, or get you to a lower level of assault or murder (as the case may be), but it’s not a full defense.