Devs can use them to block DISPOSABLE mails, not PRIVACY legitimate emails. That’s why it is critical to remove privacy oriented email domains from such lists
Disposable mails (one time mails) can be a problem for webmasters. But PRIVACY mails or ALIAS mails is PERMANENT addresses. So there is no way that they would be deleted at no additional situation. They gonna be deleted only if webmaster send SPAM or got data leak.
If you will use such addresses as disposable you will be simply banned (there is written in ToS)
Proton domains blocked as disposable in disposable filter (github.com)
I hope it is a way to solve this…