It is true that the early Nehruvian textbooks were written by Romila Thapar and so on, many of whom were Marxists. Sometimes, those textbooks did sort of emphasise a slightly rose-tinted vision of Hindu-Muslim unity running through the whole of the Delhi Sultanate right through the Mughals, which left room for the right wing to say this isn't history. But the reality was that all those Nehruvian historians were great historians which the right wing successors were not.