Disclaimer: I have a ProtonMail account that I pay for.
I have seen a ton of disturbing pieces about ProtonMail. Every time I've looked into them, they seem to be maliciously motivated and usually not true, or otherwise twisting of the truth. This has been a confusing thing for me because why is there a small subset of people so vehemently against them?
In this case, I'm not surprised. They say quite clearly they can be compelled to collect IP addresses - including in the linked tweet. This seems like a pretty clear cut case of them being compelled to provide an IP address. What the authorities can't do, is read that person's email. And that's what I and others pay for.
I'm not sure what there is to be upset about here? Other than perhaps France prosecuting this individual to begin with? If we had faith that ProtonMail wouldn't hand over anything to the government, why would anyone even care about having encrypted emails?