It doesn't work that way. I'm sure North Korea has laws criminalizing defaming the good name of the Supreme Leader anywhere in the world, but they can't enforce it outside their borders, and neither can HK.
That said, they can restrict access to externally hosted content for users in Hong Kong, and threaten seizure of assets in HK if the target doesn't comply.
> I'm sure North Korea has laws criminalizing defaming the good name of the Supreme Leader anywhere in the world, but they can't enforce it outside their borders, and neither can HK.
There's a lot more extradition treaties with HK and the PRC than there are with NK. Any country that China can exert significant pressure on could detain and extradite you if China decides you have broken the HK NSL.
A basic principle of extradition is that the action has to be a crime in both countries, which is why nobody extradites Saudis convicted of witchcraft or homosexuality.
That said, they can restrict access to externally hosted content for users in Hong Kong, and threaten seizure of assets in HK if the target doesn't comply.