It has lots of religions and cultures, yeah. But there is a dominant one. And like the US is a Christian nation de-facto, India is a Hindu nation de-facto.

The bigger driving thing is that the party in power has two massive things in their favour: widespread economic growth and prosperity.

While India mostly runs through coalition politics, there are two broad bands: the nationalist religious-fundamentalist market-economics band and the high-regulation nominally-secular band.

It's quite nuanced, but ultimately, India has raised 400 million out of poverty in the last 20 years, electrified vastly, and built rail and road infrastructure at a crucial moment in their demographic transition.

The resulting goodwill is of the "it's about the economy, stupid" sense but also a national feeling that perhaps the "others" were, after all, "holding us back" because the current opposition presided over a period of administration over many decades where setting up businesses required paying off the right guy, etc.

To make it worse, the opposition coalition head is a dynastic scion who is not very smart.

So, the shift to the right is natural because the right is the only one giving them anything.