The argument is not that caste is the same as race but that the use of caste as a marker is an additional burden placed ONLY on Indian employees and is therefor

The argument is not that caste is the same as race but that the use of caste as a marker is an additional burden placed ONLY on Indian employees and is therefore based on race or national origin. If you promote only upper-class Indians and no lower-class Indians while promoting other races regardless of caste then you are discriminating against Indians because other races/national origins do not have to clear the additional caste hurdle.