> Technically, the first amendment applies only to state actors, not private entities.
That's probably not what the person you're responding to is talking about.
Americans have this unfortunate tendency to harp on and on about 'free speech' in contexts where the first amendment obviously does not apply, or, even more intriguingly/ironically, where the first amendment pretty clearly states the exact opposite.
For example, if some non-government-owned platform (such as a social network) bans a user, and that user says "My free speech rights are being infringed".
Whereas what the 1A actually states is the exact opposite: That platform has the right to ban that user, and the government is constitutionally restrained: If the government were to make a law that forces this social network to unban this user, that'd be the 1A violation.
Then there are only 3 options:
1. That user wildly misunderstands free speech. And given how common this is, 'most americans' is perhaps [citation needed] but the sentiment is understandable. It's not just that "My free speech!" is so common, it's also that articles about some incident pretty much never talk about this. Lawyers, legal wonks, legal podcasts that sort of thing - they talk about it, but, niche audience.
2. The meaning of 'free speech' in the sentence 'this social network has banned me; my free speech is being infringed' is not referring to 1A but to the concept as a general principle; a principle that is orthogonal, or even mutually exclusive with, the definition of 'free speech' the way 1A intends it.
3. They know exactly what 1A means but they are lying through their teeth in order to get some internet group ragin' going on.
If we make a habit of assuming good intentions, the nicest choice is option 2.
The somewhat famous "Section 230" covers part of this, and explains some of the pragmatic reasoning behind MCAC v Halleck: If you hold private companies responsible for having infringed free speech rights, then private companies are going to bend over backwards making clear they are not going to moderate. Anything. For any reason. Legal reasons, you see.