Reminder, that this was in response to the Supreme Court of Brazil ordering this platform to remove certain users. They don’t need to build a firewall, this can be dealt with using international treaties and laws. US government often cracks down on websites that break US law without building a firewall. There are other levers to doing it.
Also, they don’t need a firewall, ISPs can block domain names (which the courts can force them to since they operate in the country) very easily and is used across the world.
I would include ordering blocking by local ISPs in "build a firewall". It seems what has happened here is Rumble is doing the blocking. A mechanism existing by which Brazil can force a company with no presence in Brazil to block access to web content strikes me as problematic.
Of course when a company is trying to do business in a country, it needs relationships with local companies, access to banking and payment infrastructure, etc... and governments can certainly prevent those from doing business with it. It doesn't sound like that's the issue here though.
If there is a mechanism by which the government of Brazil can force a company based in the USA or Canada to block visitors to its website, I would like to know the details so I can advocate that the USA withdraw from the relevant treaty. I'd apply the same logic to the USA trying to force foreign websites to shut down or block visitors from the USA.
Also, they don’t need a firewall, ISPs can block domain names (which the courts can force them to since they operate in the country) very easily and is used across the world.