India has its own problems with class/caste and the language that surrounds it. Officially it’s no longer in play, but there are knock-on effects.

“filthy and undesirable.”

This already means something in the old caste system, specifically about the lowest “backwards caste” people (“untouchables”). Not to say that everyone involved has old-world bigotry in their hearts, but for those that do, this is likely an especially cutting insult.