I normally agree with xkcd, but this is a huge straw man.

It's not the government oppressing you, but you are being oppressed. It's not the government restricting your speech, but your speech is being restricted.

People complaining about their speech getting restricted aren't saying "...by the government" and it's a cop out to pretend that's what they're talking about in the first place. That's not the conversation when it comes to canceling and deplatforming. That's not what people are complaining about. When people say "the right to free speech" in this context, they aren't talking about a specific legal, constitutional doctrine. They're talking about the social contract. They're saying, "hey, we generally believe in freedom as a concept, why are other people shushing me for voicing my opinion?"

Note I'm not a "free speech absolutist", I don't think we should give everyone a megaphone and tell em to have fun. Sometimes canceling is the appropriate response. There's a lot of social media assholes out there stirring up shit and they should get muzzled.

But this particular argument is bullshit.

The argument we should be making is this: what you are saying is itself so heinous and dangerous that it is a violation of the social contract. The government is not silencing you, but we will.

And we should also keep in mind that just because the government isn't silencing someone, that doesn't mean it's perfectly fine that we do. Mob mentality is a thing and sometimes we (the mob) can go too far. We should be measured about canceling and deplatforming.