The advantage for Navdeep Saini and Mohammed Siraj is that both of them play for RCB, which happens to be Virat Kohli's IPL franchise. Earlier there was a "CSK quota" in the Indian team, through which Mahendra Singh Dhoni got players such as Kedar Jadhav selected for the Indian team. Now this CSK quota has been replaced with the RCB quota. I am not saying that Saini and Siraj are bad players. But it is a fact that more deserving (or even equally deserving) players get overlooked in their favor.
This is true, but this doesn't mean that Kohli or MSD were wrong. If Rohit was the captain, he would probably focus on MI players too. They got to work with these players and have experience playing with them which is why they trusted them.
The fact that he plays for SRH shouldn't be held against him. And the Indian selectors need to tell Kohli that he should not get too biased while selecting the playing XI.
His recent performances helped him get noticed, but he still has a long way to go. 1 or 2 good performances are not enough to judge a player in any sport. He needs to be given more opportunities though.