Do you have any examples of Twitter arresting or imprisoning people for speech, or acquiescing to government censorship? Perhaps you are instead to moderating their private platform and enforcing community guidelines? I understand the latter can be annoying, but it is a mistake to conflate the two, as free speech is something very special and important and in the US is in fact codified into the Bill of Rights.

TL;DR free speech is between you and the government, not between you and someone else or some other company.