The post says that "Sign in with Apple" will issue emails on @private.icloud.com but "Hide my email" will continue issuing addresses on @icloud.com
These are two separate services. The problem was with the latter not the former. If the service decides to block @private.icloud.com they might as well remove Apple's sign in button.
These are two separate services. The problem was with the latter not the former. If the service decides to block @private.icloud.com they might as well remove Apple's sign in button.