Effective free speech
(To fend off time-wasting digressions, remember that freedom of expression refers to expression of opinion or artistic expression. Things like threats, libel, doxing, and harassment are not freedom of expression and have never been protected as such. Obfuscating the distinction is just another tactic the enemy uses to confuse the issue and undermine real free speech. "Blasphemy" and so-called "hate speech" absolutely are free speech -- they are expression of opinion, however extreme.)
In cases where a corporation or other non-state actor tries to shut down the expression of an opinion, the enemy likes to claim that "that isn't a free-speech issue -- the First Amendment only prevents the government from silencing people, and this isn't the government". The immediate issue, of course, is that freedom of expression is a general principle, whereas the First Amendment is a law relevant to only one country. The two are not at all the same. Freedom of expression is a value worth defending no matter where in the world it is under attack; no one claims the First Amendment applies in Afghanistan or China, but I still feel just as concerned about censorship of ideas there.
Beyond that, the claim repeats the classic libertarian error of believing that the only attacks on freedom that matter are governmental ones. Libertarians ignore the power of corporations, religions, criminal gangs, and other non-state actors which in many situations pose a greater de facto threat to individual freedom of action than government does. The same applies to freedom of speech. Imagine you've been invited to deliver a lecture, to an audience which signed up to hear it, on a topic of importance to you. As soon as you start speaking, some guy with a bullhorn stands up and starts bellowing hateful nonsense so that the audience can't hear you. Your First Amendment rights have not been violated -- that guy isn't from the government -- but your freedom of expression certainly has been.
This point does, of course, raise the issue of the conflicting right of owners of platforms to refuse to provide a forum for views they find abhorrent. The line must be drawn at the point where limitation of content becomes de facto prevention of that content being effectively made available at all. At one extreme, the fact that I don't allow (for example) pro-censorship or anti-Brexit comments on my blog is not censorship -- a blog is clearly an online soapbox for the views of one person, no one else has any claim to any "rights" on it, and I am not preventing such views from being expressed more generally, since it's very easy for the person who wants to express those views to do so on their own blog or in some other context over which I have no control. At the other extreme, it would clearly be wrong to allow internet service providers to censor viewpoints, since that would effectively block those views from being expressed at all. The case of major platforms like, say, Wordpress or Tumblr is very close to this -- whenever they try to ban certain types of content, it generally results in strong pushback from users, and rightly so.
Another popular anti-free-speech gimmick is to frame the issue in terms of "consequences". The enemy says, "you have the right to free speech -- you just don't have the right to avoid consequences for it". In practice, this is defending "cancel culture", the practice of hounding and harassing people for expressing ideas that somebody doesn't like, getting them fired from their jobs, etc. Of course, this is just the guy with the bullhorn shifting to pre-emption. Somebody threatening you with harm if you say things they don't like is clearly trying to frighten you out of saying those things, in whatever forum, so it is an attempt at suppression of free speech.
In any case, we all know whose language this is. It's the language of the gang of over-muscled pea-brains with baseball bats lying in wait for you in a dimly-lit parking lot. "Yeah, the law doesn't stop you from being a flaming faggot any more, but if you act like one in public, there are gonna be --" slaps baseball bat against opposite palm with a loud thwack "-- consequences." Even when the baseball bat is replaced by doxing and nasty letters to your boss and neighbors, the functional effect and moral status of the action remain the same.
If you're a typical reader of this blog, you really don't want silencing people by intimidation to become an accepted tactic. Remember, a lot of the people who'd like to shut you up have guns, and you probably don't. The proper response to speech you don't like is contrary speech, not threats or bullying.
Eye update: The visual disturbances have definitely subsided to some extent. It's almost two weeks now since the original diagnosis, so I'm starting to feel less anxious about the risk of this proceeding to retinal detachment. The disturbances remain annoying, though. I can see OK, it's more a problem of constant aggravation and distraction. I have a follow-up appointment with the ophthalmologist in a couple of weeks, so I should know then what the final outcome is.