This information was just as clearly and easily accessible by the guy who was caught, as it is to you, and to me. If you’re going to commit crimes using a cloud service, the onus is really on you to put in a minimal amount of effort to familiarize yourself with what is protected and what isn’t. Proton is extremely up front about this, and give you all the information you need to be safe.
Proton never advertised to a single user that all your data is safe from the Swiss government. On the contrary, their main selling point is that the Swiss government is the primary driver of their secure offering. They encrypt what they can using zero trust encryption, and that is left over is secured by the Swiss Governments laws regarding businesses sharing information with foreign governments.
Proton promised to not comply with direct requests from foreign governments and they haven’t.
Proton promised to encrypt all the data they feasibly can so it was safe from Proton being able to hand it over to even Swiss authorities and they have.
Proton is not responsible for user error, nor the willful ignorance of its users.