People are free to insult others and you are free to counter-insult them. And you are also free to write an open letter asking people to try to discuss their issues, rather then insulting each other, circulating petitions against each other or getting each other fired.
>People are not required to express only opinions you approve of.
This is what you might call the "doctrine of the second speaker". Alice expresses a view Bob finds offensive. Bob calls for Alice to be fired. John says that people shouldn't be fired for expressing offensive views. Then Tom points out that "People are not required to express only opinions you approve of." After all, Bob's call for Alice to be fired is protected by the first amendment, therefore (?) it's wrong to critizise people for calling for others to be fired for offensive views.