I think you're confusing "weak and strong classes" with "protected and unprotected classes"
For example, national origin is a protected class and there was a case a few years ago where the EEOC got involved. It was a company owned by Indian-Americans(?) (might have been another nationality) who routinely turned down non-Indian-American job seekers (mostly whites) solely because they where non-Indian-American and they pretty much only hired other Indian-Americans and Indians. This was official policy.
So everyone's national origin is protected, no matter what it is. Everyone is in a protected class.
But say, people who have finger or face tattoos could be turned down for a job solely for having finger and face tattoos because people who have finger and face tattoos aren't a protected class.
For example, national origin is a protected class and there was a case a few years ago where the EEOC got involved. It was a company owned by Indian-Americans(?) (might have been another nationality) who routinely turned down non-Indian-American job seekers (mostly whites) solely because they where non-Indian-American and they pretty much only hired other Indian-Americans and Indians. This was official policy.
So everyone's national origin is protected, no matter what it is. Everyone is in a protected class.
But say, people who have finger or face tattoos could be turned down for a job solely for having finger and face tattoos because people who have finger and face tattoos aren't a protected class.