This is quite a slippery slope. If I host a website in one country, I do not necessarily care where people access my website from. It is not like I actively provide a service to them - they just use internet (decentralised network) to access it. What if I publish a newspaper here, someone takes it where the contents are illegal, am I accountable?
IMO the question is not if such services should be held accountable by local laws but how they should be held accountable. I think it would make more sense to go after the UK entities profiting from the endeavor: advertizers and financial institutions involved.