How did Sai Baba's behavior challenge the caste system and traditional ideas of ritual purity?

Sai Baba consistently challenged the rigid social structures of his time. Chapter 7 explains that for him, caste did not matter in the slightest, and there was no distinction of birth. The most devout Brahmins and keepers of the sacred fire (Agnihotris), who were typically very concerned with ritual purity, would abandon their pride and prostrate before him. This amazed onlookers. The chapter further illustrates his transcendence of purity rules by noting that his mind felt no disgust even if a dog were to put its mouth into the food in the row of Fakirs. This showed he had no ego regarding the body and was the same to all, regardless of caste or species.