Author has no clue about what is Democracy and what is secularism. A country can be democratic but not a secularism. Democracy means people chose their own govt(Pakistan is also same). Secularism means religion does not matter for the jobs.
We had a Muslim head of state in 1967 (Zakir Hussain).
APJ Abdul Kalam - the President you refer to- was one of India's most beloved Presidents because he holds a double Ph. D. At the time he was elected, I think the Indian cabinet had the highest number of Ph. Ds in the world, for political (non-appointed) positions.
Although, number of Muslims educating their children are rising, specially in cities. And such people have no hatred towards anyone on religious lines.
Biggest achievement of India would be to ensure that every child goes to a proper school and get modern education and not some religious BS in early years