On topic - I believe this is a foolish move by the Indian government and it's just a matter of time before it is struck down by the judiciary on constitutional grounds - and rightfully so IMO
There are religions, there are kingdoms (political) and there are ethnic groups. The trouble with asking for a black-and-white history is that these often overlap and the existence of some distinctions (usually religious) blind us to others (usually ethnic).
The subcontinent except south India has generally been a common ethnic group [with the occasional infusion of invading armies]. The region has typically been congruent with the dharmic religions. Even with regime changes populations remain largely similar - though the ruling class might see some changes. After the advent of Islam many populations converted but ethnic and political brackets remained unchanged (Aurangzeb's empire, Ashoka's empire and British India were largely the same).
From a historical and anthropological perspective - and there's a great thread on PDF somewhere that posts the findings of some genetic studies across populations in India and Pakistan - modern the people of India and Pakistan have more similarities with one another than with other ethnic groups - such as the Persians, Burmese, Chinese and Central Asians. The present day religous divide does not preclude these similarities.
First off, there is no such thing as 'Hindu civilization'. Hinduism as a religion once stretched from Afghanistan to Indonesia; that does not make them 'once apart of the Indian civilization'. A Punjabi/Sindhi would have more in common with Kashmiris, Pashtuns and Baloch than with Indians.
There are religions, there are kingdoms (political) and there are ethnic groups. The trouble with asking for a black-and-white history is that these often overlap and the existence of some distinctions (usually religious) blind us to others (usually ethnic).
The subcontinent except south India has generally been a common ethnic group [with the occasional infusion of invading armies]. The region has typically been congruent with the dharmic religions. Even with regime changes populations remain largely similar - though the ruling class might see some changes. After the advent of Islam many populations converted but ethnic and political brackets remained unchanged (Aurangzeb's empire, Ashoka's empire and British India were largely the same).
From a historical and anthropological perspective - and there's a great thread on PDF somewhere that posts the findings of some genetic studies across populations in India and Pakistan - modern the people of India and Pakistan have more similarities with one another than with other ethnic groups - such as the Persians, Burmese, Chinese and Central Asians. The present day religous divide does not preclude these similarities.