1) Given that it has been a central concern of the left for three centuries, it should surprise no one that a letter supporting free speech rights was signed by leftists. It should also surprise no one that various neoliberal ghouls whose demonstrated contempt for free speech is exceeded only by their capacity for hypocrisy also signed it.
2) One might think that the overwhelming response by the left would be to expose the latter, citing their cynical and opportunistic brandishing of a right to free speech they routinely deny to others.
3) Alas, what has occupied many of us has been something entirely different albeit familiar, namely issuing a constant stream of denunciations of those on the left who signed. Most of these targeted Chomsky, probably the most high profile signatory but also the most predictable with a sixty year record of signing similar appeals.