Wait. Someone actually sued YouTube because they weren't allowed to say something?
Let's be clear here...
The first amendment does not give you free speech. It prohibits the Government from telling you what you can and cannot say.
If YouTube takes down a video where you're spouting off stupidity, they aren't denying you your first amendment rights. They're stopping an idiot from lowering the average intelligence level of the user base.
If an admin on fediverse blocks a gab site, they're not stifling free speech, they telling a group of fucking dumbasses that their shit isn't welcome here.
If you look at how tech companies like YouTube et al classify themselves under law, they (the sue-er) may have grounds. YouTube can't be sued for user content because they're a "platform," but I'm willing to bet they then claim they can take down posts because they're a "publisher" who can make editorial decisions. Platforms are like the public where you can stand on a soap box preaching what you will. No one has to listen to you, but you have a right to do it.
For why the distinction is important, publishers are liable for what they publish by law; but there is an exemption for public platforms online in the US, which I want to say was in section 203 of the US Communications Decency Act. It does not hold tech platforms liable for posts by their users.
A bunch of technomancers in the fediverse. Keep it fairly clean please. This arcology is for all who wash up upon it's digital shore.