One doesn't need to write perfect documentation to point out bad documentation. That said, I was hoping for more concrete examples.
Agreed. Calling something 'garbage' and providing no concrete examples isn't really constructive feedback. It is just name calling.
And this should be concerning. If Apple wants people to use Apple Sign In, they should do more than mandate its use. They should make it easy to implement, or, at the very least, provide clear documentation.
Instead, I've had to rely on other documentation outside of Apple that all start by sharing their disappointment with Apple's documentation on this subject, and then try to decipher what Apple is doing.