Very convenient for you to define what was or was not India. What did the Arabs/Afghans attack then? Even if there were multiple states how does it justify those barbaric attacks and taking over other people's lands and massacres and destruction of their places of worship?
Why is it wrong for USA to attack Iraq or any other Islamic country? There are multiple Arab/Islamic states, so it should be OK as per your twisted logic.
Hyderabad had just 10% Muslim population. How was it Muslim.
East Pakistan or Bangladesh is anyway a different story.
It was a follish idea of some idiotic politicians. India is not a Muslim country to join OIC. And OIC is definitely not a prestigious organization by any stretch of the imagination!