Not because it’s Apple, but rather because Apple are exploiting their position as iOS App Store gatekeepers to require developers to add Sign In With Apple. Mozilla don’t have this position / power.

I think people would have the same issue if Google required ‘Sign In With Google’ in play store apps that have Facebook login, and returned throwaway / proxies email addresses.

I haven’t seen anyone upset over the feature set. The only complaints I’ve seen are those uneasy with Apple’s forceful hand. They are both the gatekeeper to the store and now gatekeeper to the login. This is happening at the same time they are being investigated for anti-trust.

> they’ve been implementing privacy features for several years…

Yet this one is not a pro-privacy feature, it's an "apple owns your privacy" feature. Apple will control your account access and even be able to read your emails. Sure you trust them, but in the future they 'll use it to push their own ecosystem (like apple payments) to developers. We 've had single sign-ons for too many years to know that any ecosystem lock-in is a bad thing. As bad as email sounds, it's still the free-est , most decentralized login provider available.

> If Mozilla or name your blessed organization of choice came up with this system, most of them would be fine with it.

Mozilla came up with Persona, which would be great if they pushed it further and perhapps provided an anonymous email relayer like this instead of being based on existing email providers. With Mozilla the big advantage is that your account is not tied to any other service, real name, credit card etc. I wouldn't use Apple Login to sign up to a porn site, despite the high standards of apple's security.