The mistake my dear friend, Amitabh made is by listening to his friend Amar Singh.
Amar Singh is a politician who has vested interest in creating a vote-bank of Hindi-speaking migrants in Mumbai with the aim of gaining political power in Maharashtra.
Amitabh Bachan listened to his friend Amar Singh and became a "UP Brand Ambassador" and made ads like "UP mein jurm kum hain"
Any ordinary person, then is bound to think that Amitabh Bacchan is taking a political stand and that's where the problem lies.
Indulge in politics and expect politicans from the other end of the spectrum to counter you.