That’s not really true. The Ofcom representative said “not allowed” not “unable to”. Even if cocaine is legal in my country, I’m “not allowed” to sell it to British consumers by the power of the British authorities. The British authorities may not have legal authority in my jurisdiction but they can take action in their own, including issuing penalties and stopping my deliveries at the border.
That sounds so gross. Why do British people tolerate that? It’s as if British people belong to their government.
But are you allowed to post pictures of your cocaine on a website that is not in the UK?
But if a Brit comes to your country and buys cocaine from you, in person, you wouldn't expect to be convicted as a dealer in the UK.
Ofcom has a bad handle on web requests. Clients connect out. 4chan et al aren't pushing their services in anyone in the UK.