The option in "Sign In With Apple ID" to provide a randomized email address that proxies to your own, alongside the boolean, would do a lot to mitigate this. Of course, Apple can associate you with your usage of the site (and it's worth keeping a close eye if they start to pivot more towards advertising as a revenue stream), but the site itself would be unable to.

That is a yet to be solved problem. But people are working to make sure that doesn't happen.