For sure, email is an insecure means of communication. But, that wasn't the request of the OP. They're not asking for an e2ee messenger recommendation, but thoughts on PM. And I provided an honest suggestion that they simply cannot be trusted, regardless of whether or not they complied because "it's the law".
Considering PM is basically a honeypot at this point (can't trust they're not monitoring with a gag order preventing warrant canary), I wouldn't recommend them even to my enemies.
Alexa Academy