Yeah. What email domains should even be whitelisted? Certainly not gmail, you can create infinite alt gmail addresses. Unless you also ban the extended emails. Which is a legitimate feature to use. Maybe allow one extended email address per one base email address? This is getting a bit difficult to implement for your average Joe hosting a Lemmy instance. You can get a trial Outlook for Business or something account to get a bunch of emails on Microsoft's business email domain, onmicrosoft.com.

Then what about privacy focused email providers or personal domains? Why should users of those be punished just because a bunch of bots?