To be clear I don't hate muslims / christians but the expansionist attitude of few religions. I believe Savarkar's Hindu Atheist ideology, for all his faults, is the way forward for India.
The problem as seen by many right-leaning people is that girls of other faiths (Hindu/Christian) date with low-status-but-high-pretention Muslims, and marry them or if there's opposition by family, elope with them. They also generally get converted into Islam. But the opposite happening (Muslim/Christian getting converted to Hinduism, especially) is very rare in comparison. Also, (non-urban or previous generation mostly) Muslims have multiple wives and have many more children than others. There are anecdotes these women are pressured to have more children by those Muslim families, I don't know how pervasive that is. We can't disagree Islam has some extremist attitudes. (Sadly Hindu leaders also calling their followers to have more children, this doesn't solve the problem)
Due to minority appeasement politics played in last 70 years by Indian National Congress, Muslims also enjoy some more privilege than Hindu counterparts. This despite most of them being ruler/trader class in past (so unlike Scheduled castes). Now the game is majority appeasement and Congress has not caught up. Thus BJP is only player in the town.
A COVID19 superspreader event was an Islam religious event which also villain-ized them more in the eyes of majority.
Lastly, there are always communal fights in many parts of India and each side sees the other as enemies that must be extinguished. (There are statistically exceptional states like Kerala, but again Kerala is very educated state).
Doesn't help some of the practices of Muslim citizens irritate everyone else, like high sounds in mosques and "atther" or whatever that's called smell in public transport.
All this can be used to create a common enemy for majority of youth and boomers today.
Modi is a lot like Trump, but also intelligent enough.