I think it's class hatred. The scion of India's Congress party, Rahul Gandhi, represents the most upper class person of India (among the 0.1 percenters.) He has a Harvard and Cambridge education, an amazing pedigree stretching back to the Founder of India, Pandit Nehru. A family that gave three Prime Ministers, two of whom were martyred for the country. Sonia Gandhi being a foreigner was seen aloof to most Indians. They were ripe targets and are labeled non-Indians.
For some reasons, Indians in the hinterland states have developed a strong resentment against the liberal elites such as those in Congress party.
They think Modi is one of their own. He looks like them, talks like them, and acts foolishly without thinking. Does not care about protocol or etiquette. They see their own reflections in Modi. India was run for 70 years by the liberal elites of Congress. So now it has changed in the reverse direction. Now good education, fluency in English, and etiquette etc. are no longer important. A bunch of Jahills want to run the show and they call themselves proud Indians.
Of course they are willing to ignore the fact that Modi is only deceiving them as all con artistes do. He is nothing but a paid employee of 10-15 crony capitalistic businessmen running the show in present India. They include Ambai, Adani, Hinduja, Ruia Group etc.