True, but as long as there's no court order it's up to the big companies if they enact, say hatespeech, clauses in their private TOS'es and shut down sites.

In theory, but there are tons of gag orders and indictments that you never hear about, by design. Warrant canaries are a thing for a reason.

but I find it more plausible that there's either an expressed or silent agreement between a lot of the large tech companies with giants such as Facebook with Zuckerberg and Google with Schmidt as examples of companies with similar politics and ideology that encourage censorship.

Totally possible, I don't doubt it. I just also think there are governmental forces involved. When things get to this large of a scale, it's hard for it not to be that way. The government always gets involved in anything this influential. So the policies of facebook and twitter and so on reflect, at least in part, the hand of the government. Because of all these indictments and other forces acting upon giant companies like facebook and twitter.

The 1st amendment doesn't apply to me nor the majority of the users of the big tech services. That aside, if the coordinated and one-sided censorship and takedowns continue (regardless if they're private or law enforcement) I believe the US users will argue that certain big tech platforms, social network and hosts included, aren't protected by section 230 of the Communications Decency Act, which would be a big problem for a lot of big companies.

I think you are right. Hiding behind the shield of "censorship is okay because it's private companies doing it" falls apart when it's something that literally hundreds of millions of people use, and should probably best be re-classified as public infrastructure, like the electric grid, mail, or firefighters.

The end goal is to better control public discourse. Your scenario and my scenario are not mutually exclusive, but rather complimentary.

Here's one thing, from 2015, just the tip of the iceberg: https://www.theguardian.com/world/2015/nov/12/facebook-says-governments-seek-more-and-more-user-data-and-takedowns

This type of behavior by the government is happening on reddit, on facebook, on instagram, twitter, and many other giant platforms.

They'd be stupid not to, from their perspective. And who is stopping them?

Section 230 sounds like a great route, but what senator is going to vote for it when facebook (and twitter, instagram, etc) each throws a couple hundred thousand dollars their way to prevent it?