I don't have anything major to add to what I've already said. We have indeed an ethical obligation towards our (future) customers, that's exactly why we couldn't fulfill Ofcom's demands - that would literally be illegal in our jurisdiction. Sovereign countries have their own laws (not the UK's), and in addition to these we also provide strong moderation tools. So for now we have to block the UK. We're in closed alpha stage and have a long way to go so this is purely a matter of legal prudence.

By the way, I've worked closely together with argumentation theorists at university for many years, so I know quite well what a slippery slope argument is. You should know that not all of them are fallacies.