Just because someone lives within the boundaries of India doesn't give you the right to dictate anything to them outside the bounds of the Indian Constitution, something Malhotra (tell me, does he have _any_ formal training in historiography?) would do well to remember.
So maybe there was an Aryan migration or the IVC merged with them somehow. Do you really think that everyone who might hold the Aryan invasion hypothesis automatically thinks Indians are bovine Hindu Dravidian stock who never stand up for themselves? Try telling that to the Jaipuris or the Marathas for starters (very Dravidian, those two). This is all the worst kind of caricaturing you are engaged in.
This is why it is still by far the most accepted theory in academia and it makes the most sense (wishes of Indian nationalists not-withstanding).
Also, just curiously... how do you get an Indian origin of the Indo-European people out of the link you posted? From the summary, it states nothing of the sort and merely confirms that there are genes in common between Europeans and some populations of India... a fact most everyone agrees on. More endogamy doesn't imply origin by any stretch.
http://en.wikipedia.org/wiki/Indigenous_Aryans
"Politicized theory". Not accepted by mainstream academics. Most likely not how it happened. Please don't confuse nationalistic pride with reality.
Don't ignore the evidence!
I do know what an abugida is, what are you driving at?
Other Aryans could have easily gone down the Sarasvati and Sarayu into north India. Others went from the Indus into Kashmir and Afghanistan, and into Central Asia. Others went into the areas of Gujarat and Sind, and over through Persia and the Gulf region. This is how the Sumerian civilization was founded, along with Babylonia. From there they went farther into Turkey and Europe.
This seems to indicate that not only did Aryans exist, but that someone descended from them could have made it onto the map in TFA. Which isn't surprising: people move around all the time, and over millennia they and their descendants certainly could move from India to Europe.