People outside the U.S. should care about this because so much social media is based in the U.S..

i.e. If you post an anti-MAGA meme to Facebook or reddit from an identifiable account you could be charged as this man was. Perhaps the U.S. will try to extradite you. (I would hope most nations have sensible checks and balances to prevent extradition over this sort of thing, but it would still be a PITA.) However, the U.S. might also choose to wait and then arrest you if you ever travel to or through the U.S..

The U.S.'s slide away from freedom of speech could have a huge global impact on people who might think it doesn't effect them. We are far too reliant on American social media.

Canada, the E.U., etc. should be looking at protections to prevent social media companies operating servers in their jurisdictions from sharing information with the U.S. government. It's no longer a hypothetical situation. There is a real threat that is clearly evident now.