Kulturkampf

[benji]

But if we can't extradite an american spook for shitty driving that killed someone, we're not gonna get someone extradited for shitposting on twitter.

The United States not only passed a law refusing to recognize British libel rulings, it explicitly refuses to extradite people for such things. Extradition in general typically does not work for things the country doesn't recognize as crimes.

In any case, I think that cop was just being a cop and sounding vaguely tough, not laying out a theory of jurisdiction.