l am sorry that you are confused about the rights people have under the First Amendment. Calling for a boycott is protected speech. Boycotting is protected speech. It is one of the oldest forms of protest in America, and it is a protected form of protest today. Sorry if that hurts your feelings. Also, saying, "You shouldn't listen to this doofus; he's awful and his opinions are awful" is not "silencing" anyone. It is responding to speech with speech. Moreover, a private company like Medium or Twitter can set boundaries about what speech is/isn't allowed on their platform, because they are private companies with the right to decide what speech they will/won't support. If Twitter boots Donald Trump, he has not been silenced. There is no constitutional right to have a Twitter account. There is no constitutional right to say stupid things and not be criticized, laughed at, mocked, shamed, or publicly ridiculed. There is this: a constitutional right to say what you think without being punished for it by the government.

A lot of purported free speech advocates are way too fragile for actual free speech. They want to be free to say dumb things without being criticized, and they take criticism as an infringement of their rights.

I am not so fragile, and my advice to you is to suck it up.