Of course, there's nothing stopping you from using a git-only email address (nospam-6thbit@yourdomain) and routing that to /dev/null. GitHub can't change email addresses, but you can.
They only do that if you set up that specific email on your account. Not if its 'any email other than the noreply one'.
> When you push to GitHub, we’ll check the most recent commit. If the author email on that commit is a private email on your GitHub account, we will block the push and warn you about exposing your private email.
Perhaps my usecase is niche, but I sometimes work with other git servers from the same machine with different emails and I don't want to set up all those on GH. Global settings don't help here, per-repo settings help but this doesn't come along when you clone a new one.