to be clear (and this is kinda addressed at everyone in this thread because it was bothering me a few days later): I don't disagree with any of what you said here. I don't even live in the UK anyway, and I'm inclined to believe the whole plan is idiotic.
What I'm frustrated about is people's inability to have an actual discussion it because they're so affected by emotion (like I said: "people can't reason about a tradeoff between two principles"). One can reason about the tradeoffs rationally, instead of by intentionally misunderstanding anyone who disagrees with you and casting them in the most negative possible light, accusing them of wanting police states etc --- and then come to the same conclusions! nothing about using reasoning prohibits the same conclusions --- but because you now engage justly with other people, there's a chance of actually changing their minds.
I am very disappointed in the caliber of replies in this thread. This kind of thing: "Is anyone else as stunned as I am by how many posters on tech websites have suddenly gone full anti-free-internet and embracing the police state?" is idiotic. The people they're replying to aren't pro-police state, they're anti-'social media for kids'. They would welcome better solutions to the same issue. but as soon as an angry person misattributes the other sides' opinions to philosophies they didn't espouse and would actively disagree with, all attempt at dialogue---even the kind where you chance someone's mind to agree with you---is fucked.