Yea, the multiple uses of a single account strikes me as the bigger issue here. Why would my email access by tied to my ability to comment on a video sharing website? Same issue as Oculus requiring a facebook account.
But if your email address is “name@provider.com”, you’re kind of screwed.
…and chuckling ruefully as I recall walking recent college grads who are far better devs than I am through what needed to happen for SendGrid to actually work for one of their project, having to start with “what is an MX record?” and “where is that controlled?”