As a user I'm a huge fan of it. It's how I use a lot of services these days without tying them to an email account.
Your position is immoral. Coercion of any kind is bad. Approving it for egoistic reasons is equally bad.
You could freely support apps that do use Apple sign in voluntarily, but you like it that the developers are forced to provide it. Immoral and pathetic.
For each app, you have a new button to consider / remember which one you used:
* Login with email
* Login with Google
* Login with Facebook
* Login with Apple
There's a "keep me signed in" feature too. Or if this is a serious source of confusion, use local device storage to keep track.
In practice I don't consider anything for each app. If it's worked I used gsuite. If it's personal I used Apple. OAuth is the new "same password used everywhere" but now we click logos.