Interesting that educated people are *more* likely to vote for Modi/BJP in India.
Maybe it is the income effect, similar to what happened in Brazil in 2018
India still has significant caste-based voting, and educated people are more likely to be in the priesthood caste, a BJP group (though the highly educated may not be as BJP). Traditionally, and especially in the British era, the educated were almost exclusively in this caste, though that has changed a lot in recent decades.
As far as reasons, one is that the Congress party is seen as responsible for India's version of affirmative action (which affects things a lot more than in the US since the underprivileged are a big majority there). If India is like every other country, I'm assuming the second highest caste will be even more BJP than the highest. I think the stats for education+caste would be more informative.
