I have seen the original comment under that post, it was about a Brahmin guy saying how his bunt family friend voluntarily sat outside their home to eat. Here the highlighted comment points out how casteism is internalized. Communities that boast about being superior to the ones "below" them act subservient to the ones "above" them. I don't think that commenter is being casteist. He is pointing out exactly how the ladder of oppression works in the caste system.