alt Hacker NewsI never understood this. Basically every country, including the US, has libel and slander laws, and almost the same everywhere in the West. People were thrown to jail even in America for "a single tweet", the exact same way as in the UK. And for example, saying that you support violence in specific cases, like there is an ongoing riot, and you tweet "kill them all", that's not protected by any free speech laws in the world, not even the American, or any states' in America.
You can actually tweet/write agreement with acts of violence and advocate for it in a general sense in the US. The legal standard is whether that speech is a threat to imminent violence (encouraging violence at a specific place and time): https://en.wikipedia.org/wiki/Brandenburg_v._Ohio
Furthermore, defamation/libel is not covered under criminal law, it’s considered a tort so it would be a civil suit.
So no, not at all like the UK.
EDIT: But yeah sure if you want to try to defend your point, start linking cases to support the claim.