there is a world of difference between saying pakistan should not exist and the much more malicious "thousand year" quote. some indians think pakistan should not exist since in their opinion pakistan is a state that sponsors terrorism in india.
but its never part of our national narrative that we avanged 1000 years of slavery in 1971. for e.g. our history books write glowingly about the mughal age especially at the time of akbar. we read extensively about his administration, the arts, mughal painting etc.etc. similarly the taj mahal is a sign of pride for indians, not a memorial of our slavery. in the 1700's when the marathas became all powerful (before 1761, 3rd battle of panipat), our history books doesnt call the maratha rise a war of independence against the muslims. but 1857 is called first war of independence against british. sher shahs suri is another king about whom there are glowing terms used.
we also read extensively about allauddin khiljis rule, his taxation system (he was the first king to bring about centralized tax and excise collection on agriculture). nowhere does it say that we were slaves.