Whacking their knees with a crowbar wouldn't stop them from speaking either, but we don't do that when someone expresses a wrong view, nor should we try to get them fired. Free speech as a cultural value requires that people actually be free to speak. If one fears losing one's livelihood, one is not free to speak. That's obvious.

For a long time, it was the left who championed this. Noam Chomsky, an archetype of the left, has always been one of the biggest free-speech advocates in the US, and takes a far more expansive view than "free speech only means the government can't put you in prison". He advocated for Walt Rostow, a technocrat whom he had condemned in print as a war criminal, to be allowed to teach at MIT. But he's a libertarian socialist, and the left has taken an authoritarian turn.

The social-media driven ideological lust for driving wrong-speakers out of their jobs (and inflicting anything else the mob can muster) is clearly a recent development in America, and you have to go back at least to McCarthyism to find anything comparable.

To preface I'm going to be loose with the actual decision of Citizens United: Ironically, since the Supreme Court ruled restrictions on spending money was a violation of the first amendment, one could argue that losing your paycheck, and your ability to spend money you would have otherwise had, is a form of losing their speech.

I'm not sure I believe any of that but I think it is an interesting idea.

You can't have the freedom of speech when there is a chance for retaliation.