What Apple selling as "Sign in with Apple" is one of the "tool" I created to fix email spam. It is very much related. This is the problem of throwing arguments without understanding the context. If you had gone through that blog post and read the section "what is the real invention" carefully, then you would understand how "sign in with apple" system is very much related to my antispam methods.

I added some more info in an other comment. https://news.ycombinator.com/item?id=24425853