But it very clearly is not. Quite the opposite is upheld by a court.

Of course, unless, by ‘principle’ you mean ‘only under certain conditions, sometimes, for some things to be said, by some people, to some specific set of people, YMMV’, in which case I fail to see the difference to the UK (or Saudi Arabia, for that matter). You also have that complete principle of freedom to praise the prince in SA.