The issue is them having any info to give out in the first place, it is a horrendous transgression for a shop that touts privacy as their thing.
Signal demonstrated that you can decouple payment info from account info and thus they ain't got nothing to produce, MLAT or not. The least Proton coulda done is mimic that tech.
edit: are you shills illiterate, what's your deal? signal also accepts payments, the kind normal people use, like CC and stuff. and they decoupled payment info from account info, so nobody can link John Smith, Fuckville, AL to account protonshill4lyfe@proton.yo


$600