How did Sai Baba's actions demonstrate his disregard for traditional caste hierarchy and ritual purity?

Sai Baba's complete indifference to caste and ritual purity is a key point in Chapter 7. It states that for him, there was no distinction of birth, and he was the same to all castes, whether Shudra or outcaste. This is powerfully illustrated by the fact that the most elite Brahmins and keepers of sacred fires (Agnihotris) would abandon their pride in ritual purity and prostrate themselves before him. Furthermore, his lack of ego regarding the body is shown in an example where his mind felt no disgust even if a dog were to put its mouth into the food being served.