This attack actually happened years ago at a company called Hushmail. Law enforcement had the encrypted email provider serve malicious code to the target which leaked the secret key.
Hushmail operates out of Canada, though. Jurisdiction matters a lot here since Switzerland has a reputation for making it difficult for foreign governments.
Swiss authorities and security services cooperate closely with partners all over the world including the NSA. And there is a longstanding and working network of mutual legal assistance including the Convention on Cybercrime (CCC).
Cooperation isn't quite the same as cooperation. There's a world of difference between sharing intelligence on other countries and working together when conducting espionage elsewhere, vs actively attacking domestic targets. Rule of law is taken seriously, and government hacking is a thing - but the scope is very very narrow.