Yes, I've just reread it, and while I completely disagree with the issue creator's attitude, he does have a point:
you also removed all the old versions that were released under an open source license so that others couldn't continue to use out-of-support versions
I haven't verify if this is true of not, but this is just not necessary. If the author stops providing pre-built binary for newer release versions, so be it. But I think it is a little too much aggressive from the author to delete old release versions as well.
Proton did nothing wrong here; in fact, it is working as intended.
No email content or attachment was provided in this case because they (Proton) have nothing to give. Now, imagine if this user were using Gmail instead of Proton.
The article title is clickbait and is trying to incite outrage from the crowd. Don't fall for it.