These laws not only existed, they where far more stringent, prosecution far easier and the punishment far more severe. Try going back then and discussing the king/queen in a negative way.
And yet, his book was still published.
And in any case, he didn't say it to be threatening or abusive, so that's moot.
> A stark warning that this concern is not a sterile theoretical exercise
The HR policies of an American company (a country where in a lot of states you can be fired for any/no reason at all) is neither here nor there in a discussion about the UK's definition of hate crime, where that definition needs to be proven in a court of law to a jury of your peers at a trial.
Not every country adheres to such a fanatical stance on free speech as the USA, and yet seem to be doing just fine. Especially the UK, where there are restrictions on free speech. Sensible restrictions supported by the sensible population, who are not oddly terrified of their government.