> If it matters there are a lot of restrictions and there can be dire consequences.
That's blatantly incorrect. Name a bunch of examples of that please. It's the very rare exception that you can't publish something in the US.
You mention Snowden: he was able to publish the documents in the US. Numerous US media outlets published documents from the Snowden cache. It got non-stop coverage for most of that year in the US as the reveals rolled on. That the media can publish such doesn't mean the action of stealing classified documents from the government should be legal, that would be absurd.
The US Government is almost entirely powerless to prevent very embarrassing things from coming out, such as Abu Ghraib as one dramatic example. If they could do what you're claiming they can, they would have shut all of that down immediately and it would have never been published across basically all media in the US for a year.
Nixon, watergate and the pentagon papers is another obvious example where the substantial US protections for the press won out.
COINTELPRO and the Citizens' Commission to Investigate the FBI is another example. The US media was able to publish the stolen documents.
We're got a President that is at 'war' with the press on a daily basis. They hate him, he hates them. He's almost entirely powerless to do anything about them. It's clear that Trump would heavily restrict the media if he could, what greater proof could one possibly need of just how potent the protections for speech / press / expression are? Trump's administration has been leaking like crazy since day one, and the media has been publishing those leaks at will. The government can't do anything about it. They have no power to stop the Washington Post or NY Times from publishing such leaks.
The US is the only country on earth that can support a Reddit, Twitter, Tumblr, Wordpress or Hacker News, precisely because we're free to say all sorts of disagreeable or hateful things on most of those platforms. And if not, I can always build my own new site or platform. Even the most liberal speech supporting nations in Europe don't allow what the US does when it comes to speech areas that involve things such as religion, government and politics.
I can insult the police in the US on HN, and I won't be arrested for it. That isn't true in the UK as one example. They put people in jail for insulting the police on social media there.
I can insult the US President in any number of various ways across countless US platforms. Snoop Dogg killed him in a music video; they made his wife a stripper in another music video. You can mock-up his chopped off head and put it on the cover of a magazine, you won't go to jail for that. There are very few countries that afford you such expression luxury, even when it's detestable expression (the most important kind to protect).
Online in the US I can disagree with Islam, Christianity, Judaism, their followers, their practices, and so on, at will, in almost any manner I see fit. There are few countries where that remains true other than the US. Most of Europe now categories such as hate speech, or otherwise restricted speech, and will arrest you for it.
The reason the US dominates online platforms, is precisely because the US is the sole country where they can thrive when it comes to aggressively enshrined freedom of speech & expression. You can't build a Reddit in Europe and will never be able to. With the draconian copyright laws the EU is passing, it's only going to get that much worse.