Earlier quoted context omitted.
I agree with your sentiment. But, as someone who understands that not all people and companies use the same moral set as myself, this is why I've never set up 2fa using a phone. Why should I give some company my phone number? Increasingly it's become a single point of metadata to uniquely describe myself (just as my email addresses have).
> just as my email addresses have That doesn’t need to be the case though with just a little bit of effort and minimal cost. Use your own domain for email and set your account to be a catchall. Then use facebook.com@yourdomain.tld and your email address is no longer a cross site unique identifier.
If facebook was able to design and build this system, you can bet that other companies are doing this too.