Visit to Mandu (Mandavgadh)

I recently visited Mandu near Indore. Thanks to great guides ( my wife's cousin and uncle) I got in touch with a part of India's history.
A magnificent palace of Rani Roopmati and her husband Baz Bahadur, and a equally well constructed Jahaj Mahal. Though one thing really had me amazed and depressed at the same time was the construction at Jahaj Mahal. One great 'Darbar" or cout building was of a peculiar type. Outside the stone was red-yellow or of a granite block. Inside was all black stone and the walls were really thick. My wife's cousin probably seeing some confused expression's on my face beckoned me to follow him and took me at a ledge on the outside wall. There a stone was removed from the outer wall. And inside was a beautiful carving of Saraswati! I was flabbergasted! He told me that most of the buildings in this complex were Hindu buildings and temples and the Muslims who later occupied it destroyed the idols but retained the constructions by building over it.
I had read about Taj being a Hindu temple before but couldn't really believe that totally before.
This sight really got me thinking that was indeed a possibility. Eventually I saw around 3 to 4 places where stones had been removed to show the idols and deities behind it.
I felt sad that all Hindu history has been horribly scared by Muslim barbarism in the past. Yet our government tries to hide that just for the sake of losing Muslim votes.
I don't hate the Muslims but I really hate the anglicized and western educated so called secular Congress who is responsible for feeding false history thru textbooks to young Indians.