It is pretty much just scaremongering. Marijuana, like any drug, can put a person in a mental state that can serve as a trigger for a psychological condition that someone is prone to, like if someone with a family history of anxiety gets way too uncomfortably high. It’s not necessarily the drug that’s at fault - it’s having a stressful experience of a bad time. I’ve never heard of psychosis induced by cannabis though.
Marijuana is just about the safest drug there is, and I think most people could safely try it with no ill effects.
My issue was not that Andy Yen made the comment he did (as much as I disagree). My problem was the Proton account making an official statement doubling down on it.
He did make a subsequent post trying to clarify and apologize, but at this point, the cat is out of the bag, IMO. I’m switching to Tuta for email, Mullvad for VPN, and self-hosting Nextcloud for storage.