What is this in that case?

Unfortunately no. See here

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)

You are telling truth unfortunately. That’s why I asked help from community…

They rejects them because it is an abuse prevention mechanism. You can solve captcha and register without any additional information

Your can simply block sender, not only delete aliases. So it is a problem of webmaster that doesn’t respect users wish to unsubscribe

Yes. That’s why I asked help :(

Look. Outlook, Yahoo, ICloud, even Gmail provides temp mails solutions, but nobody complains or blocks them.

Also you can use something like this that will create disposable Gmail every time. So blocking Proton is totally useless

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

Unfortunately? This is true. That’s why I asked help from community!

We fighted it out from 7c filter. Now only this and this lasts. Thank you for kind words. Only community can change this bad practice!