It is relevant. There's a material difference between shipping material overseas and shipping it (and handling it) within the destination country.
If someone mails $ProhibitedItem at a USPS to the UK, then it's the job of local UK police and/or customs to reject the parcel if it is prohibited. It's the UK's problem, de facto if not de jure, because the sender is out of reach.
If someone with a UK subsidiary and local processing center mails $ProhibitedItem to their center and delivers it to someone in the UK, then that's more than the UK's problem.
Absolutely yes. If a government thinks there is stuff for sale its citizens should not be allowed to buy, they don’t stop county x making it or selling it. They block the thing from entering their country.
If the government thinks there are ones and zeros on the internet it’s citizens should not be allowed to see, they should block them from entering the country.
If that were true why is everyone so irritated by this? Just ignore it in that case. But for those people that may want to become subject to British jurisdiction in future or do other business there in future, they will take requests from Ofcom seriously.
No, real example is a British citizen picking up an American AM radio station that happens to broadcast things forbidden by the UK law, and the UK fining such radio station.
