Edit: Isn't getting kicked off twitter simply a consequence of saying something that's against twitter's TOS? What definition of free speech is Musk using?
Being banned from Twitter is a consequence of your speech, but it's also restricting your freedom to speak. I imagine Musk feels that not restricting people's freedom of speech is more important than the consequence of banning them.
That doesn't mean he thinks there should be no consequences for speaking. Just that the consequences shouldn't limit your freedom to speak.
In this case, people fired from SpaceX are still free to speak out about Musk's brand and its influence on SpaceX. Their speech has not been restricted.
The people banned from Twitter are still free to speak about whatever as well. Frankly I think SpaceX's actions limit speech more than a Twitter ban. Ex-Twitter users just have to find a new platform, at their convenience. Fired employees have just had there livelihood taken away and have to drop everything and find something new before their savings run out.
To be clear I think SpaceX was well within it's rights to fire these people, but as consequences go I see firing as far more consequential than a Twitter ban.
I'd expect them to go on a interview campaign after this actually. I think they'll be quite publicized and amplified.
People who are fired from SpaceX have absolutely no access to the SpaceX communication channels they were fired for exercising the wrong kind of speech on.
Obviously, I am not saying what these employees are saying is equivalent, but cancelling somebody for what they say is not always cancel culture.
Trying to destroy someone's life for a wholly-subjective slight is cancel culture (social cancer)
What limits freedom of speech _are_ the "consequences". It either is "absolute" in which case there are no consequences, or limited, in which case there are consequences (but then by definition it isn't absolute anymore)
If you fire someone for their opinion about their employer, or jail them for their opinion about the president, you can't be for "absolute" freedom of speech.
It's like saying "you're free to murder people, but if you do you'll go to jail".
In a strictly legal sense, you can be allowed to call your neighbor ugly. There will be no legal consequences, because of a law/constitutional amendment protecting free speech.
On a personal level, however, your neighbor might not like being called ugly, and retaliate by avoiding you or insulting you back. This is a consequence, but not a legal one.
I think, Musk view is that expression on Twitter should play a "legal guardian" type role in moderating content on the site, as opposed to say blocking negative content (and you could argue that as a site that makes money selling ads, blocking negative content could be the smart play, similar to the NYT not hiring idiots to write for them), but that the SpaceX employees, when fired by their employer, are facing consequences not on a legal but a personal level.
Of course, there's a very good chance this is just backwards rationalizing the erratic, irrational behavior of a emotionally unstable person.
Musk has only ever said he believes people should have absolute freedom of speech; he hasn't said people shouldn't face consequences for what they say.