That is because you have not interacted with parsis as much as I have.
They have a serious superiority complex related to "race" and they are obsessed about racial purity.
The fact that he has married a Maharashtrain girl would mean that he is ex-communicated from his own community, or at the very least would be seen as "lower caste".
His alter ego is merely to allow him to express his frustration in secret, nothing to do with convincing others to become a sanghi.
He loves his steak's more than he loves his hindu "brothers", that much is obvious. Similar to the reasoning by other "minorities' who oppose hindu values on similar lines.
What he desires most is going back to the "good old days" where parsis' were considered superior and he could prance around claim superiority based on fair skin and and "race". Time when Hindus were meek and humble and no so vocal about their values and desires.
He is ok with Maharastrians claiming to be superior, but to watch the rest of Hindus claim a high ground gets his "beef".