I'm guessing they weren't sure whether caste was a protected class.
Discrimination in law revolves around protected classes (race, religion, national origin, age and sex are the "big five" in the US, and subsequent acts and decisions have added sexual orientation/gender identity, familial status, pregnancy, disability, veteran status, and genetic information). If you act on the basis of that, someone can, well, make a federal case out of it.
On the other hand, if you discriminated on the basis of eye color -- pretending for a moment it wasn't correlated with race -- you might be a shitty manager, but it wouldn't be a legal issue.
Discrimination in law revolves around protected classes (race, religion, national origin, age and sex are the "big five" in the US, and subsequent acts and decisions have added sexual orientation/gender identity, familial status, pregnancy, disability, veteran status, and genetic information). If you act on the basis of that, someone can, well, make a federal case out of it.
On the other hand, if you discriminated on the basis of eye color -- pretending for a moment it wasn't correlated with race -- you might be a shitty manager, but it wouldn't be a legal issue.