Yes, absolutely, we should defend the right of people to say things that we don't want to hear, and we should say true things that others don't want to hear; but there is a difference between defending someone against the legal consequences of the exercise of freedom of speech, and using my voice to amplify their speech (as I am doing, implicitly, if I am a large corporation that presides over a platform with global reach). The former is not legally required, but perhaps is ethically required; I'd argue that the latter is not ethically required, and may even be ethically enjoined. Even if I am wrong in this ethical calculation, it is a fact that there is no constitutionally guaranteed right in the US that I, or any corporation, will protect your freedom of speech, only that the government will not infringe it.