There's more theater in America, but not always.
Robert Peralta was arrested for a tweet.
People have been arrested in America for threats of violence, as they absolutely should be.
It would be absolute berzerk to suggest these pieces of shit shouldn't have been arrested, for example:
Authorities say two men who were arrested at New York’s Penn Station after antisemitic threats were posted on social media represented a real danger
www.independent.co.uk
But generally in America people are arrested and the excuse is the form of protest rather than the words or sentiment... the UK is probably just more honest about the fact the authorities don't approve of certain narratives.