It may be different in the UK. They have defamation laws that seem insane to a USA person. (Burden of proof on the speaker to prove what they said is true iirc)
I 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.
What on earth does defamation being a civil offense have to do with anything? It's a civil offense in the UK too, criminal defamation hasn't been a thing since 2010 and was barely a thing before then. If you want to confidently post how one thing is not at all like the other thing it might be a good idea to know the most basic facts about the other thing.
Maybe re-read parent’s comment? They were saying there are laws against libel/slander in every country, US doesn’t have such laws that would throw you behind bars.
I am confident in stating the UK has much weaker free speech laws and no constitution to base free speech protections on. FFS, this is the country a dude was arrested and fined for filming his dog doing a hitler salute. We have had a few cases not related to violence in the US but they usually end up overturned even when there’s a conviction (thinking of this guy as an example: https://en.wikipedia.org/wiki/Douglass_Mackey )