The stasi would blush at the surveillance foreign corporations and the British government now engage in as a matter of course

My understanding is that the Stasi were very repressive - “using torture, intimidation and a vast network of informants to crush dissent”. I’m not aware of the UK government using torture to crush dissent.

But spying on all of the public all of the time comes at a cost to society I would rather not pay. It quells dissent in the short and maybe mid term, but that extreme intrusion, ultimately drives otherwise moderate people into the hands of extremists

I don’t think the public should be spied on all the time. But if there is some way that illegal communications (like planning murder) could be intercepted, without spying on others, that would be good.

The terrorists win when we sacrifice liberty for temporary security (or whatever that quote was)

There’s a quote by Benjamin Franklin which apparently is: “Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety”. I always thought that quote was a bit weird though, because humans do give up some form of liberty in return for safety. E.g. we give up the freedom to murder other people without legal consequences, because in return we get some safety: protection from being murdered by others.