Some users may be too young to remember this, but up until the 2010s, liberals were generally opposed to all censorship by anyone, and wanted the First Amendment to be interpreted liberally to apply beyond just government actions. It wasn't until about 2017 that you started to hear liberals say, "They're a private corporation; they can do what they want," which you would have heard only from conservatives before that.
Now that some corporations appear to be shifting again and can't be trusted to censor only conservatives anymore (most notably Twitter after the Musk purchase) we're seeing the 20th-century expansive interpretation of free speech making a comeback on the left. Feels comfy, like an old pair of slippers.
I'm in my 40s and I remember it very clearly. I'm not even American, but belief in freedom of speech was the norm both inside and outside of the USA.
If you don't, I would say it's because you've forgotten that the word "liberal" in American political discourse used to actually correspond at least vaguely to what traditional dictionaries, historically recognized classical liberal authors, encyclopedias of political thought, and basic logic and reason all used to agree on. As opposed to what it appears to mean now, which seems to be something approximately like "everything that's closer to what the DNC proposes than what the RNC proposes, at any given moment".
Seeing Musk buy Twitter and start promoting right wing speech rather than left wing speech was quite the shock to these people. Suddenly the realisation dawned that corporate censorship could be used against those you agreed with, and in favour of your opponents.
(it was also amusingly the time in which the right went quiet on censorship on Twitter, for much the same reason).
Either way, it's become really apparent that most people don't have any consistent political beliefs or values, and only value freedom of speech so much as 'their' team gets to say what they want without consequences and their opponents get bullied and shut down at a moment's notice.
The right went quiet about censorship on X because there just isn't much of it. I remember at the time when people were asked to justify the claim X was censoring the left people could only cite three examples, two of which were mistakes and their profiles were rapidly restored (yet they were still being cited as examples of leftists who were kicked off the platform), and one of which was an Antifa account permabanned for ... inciting violence against the right.
In the Twitter years the right could produce endless lists of right wing people banned from the platform, and we now know there were tons of internal emails and discussions about that exact policy. The fact that nobody could produce similar lists for the left post-Musk indicates that he really has significantly improved the free speech situation there.
Now that some corporations appear to be shifting again and can't be trusted to censor only conservatives anymore (most notably Twitter after the Musk purchase) we're seeing the 20th-century expansive interpretation of free speech making a comeback on the left. Feels comfy, like an old pair of slippers.