Because he’s speaking to a British newspaper about British policies. I’m assuming the second part as I don’t subscribe to the times so cant read the article, but there are currently plans in place in the UK to introduce an opt-out framework for people to remove permission for training on their work, with pushback from big names that want to charge rent on their old works, so I assume that is the subject.

Even if he wasn’t talking about the UK at all (which I think it is clear he is from context) my larger point still stands, the choice isn’t between stopping AI and allowing AI, its between allowing AI companies to operate in your jurisdiction or AI being trained elsewhere that is out of your control. There is no option for “stop this entirely”, unless you can persuade the USA and China at the very least to sign up to it. Which they wont.