I don't see the stunt here. They are required to do so under Swiss law, otherwise they'd likely get shut down. They also have no obligation to assist in any foreign requests. afaik they are quite transparent in how they handle these requests.

Also they have no access to any of the user's encrypted emails, files etc...

If this worries you, you can sign up for a free account then upgrade by paying with bitcoin and remain somewhat anonymous.

https://proton.me/legal/transparency