Free speech should not be limited. However, those who perpetrate the abuse of free speech must be held accountable.
If one encounters the abuse of free speech, one should call "BS" on the perpetrator. Freedom also means that a citizen must take responsibility for protecting the RESPONSIBLE exercise of our freedoms.
The anonymity of the internet makes it difficult to shame or prosecute such abusers, and many abusers have no shame so shaming them would have no affect.
In the end, there may not be a solution to the abuse of free speech.