Presumably by making it "difficult enough" to misuse the tools. We don't need perfect censorship or surveillance. There are all sorts of things that are technically possible today but typically aren't an issue in practice due to some oftey fairly minor hurdles.

Aum literally synthesized sarin in the 90s so clearly it's doable yet in practice it doesn't seem to be a problem that crops up regularly.

Anyone with a bachelors in chemistry is trivially capable of synthesizing arbitrarily large quantities of high explosive in his kitchen from everyday household supplies. Yet for the most part it seems that the level of education required to figure it all out is a sufficiently high bar to prevent the vast majority of problems.