Hi @uribeamr,
Unfortunately, this is a limitation with Actions when using Social Connections to sign up and log in.
Generally, you would use a Pre-User Registration Action to block and prevent users from signing up. However, this flow does not run for Social Connections.
As a working around, we recommend using a Post-Login action to deny the users from log in based on their email domain. However, please note that this flow cannot prevent users from signing up and it will still create a user profile. It is unfortunately unavoidable.
Here is a related post also mentioning this: How to use Actions to block signup based on email domain from a social connection?
Thanks,
Rueben