US is important to India, which is why Modi is going to the US in the first place in-spite of being insulted by the US govt. He does so purely for India's benefit.
That does not mean he should he should sacrifice his personal self respect and dignity while interacting with the US. It was necessary that he paid them back in the same coin without fear. The world respects courage.
What I like about this incident is that it shows quite a few things about Modi. That he does not forget or forgive, however mighty the opponent is. That shows his self confidence and courage.
A person who is capable of Avenging his own insult is also a man who knows the value of Self Respect and dignity. He is a man who will Protect the self Respect and Dignity of India in the international arena.
Unlike Manmohan who was humiliated by congress and Rahul gandhi while he was in the US. His own lack of self respect ended up showing India in poor light in the world community. He made India into a laughing stock due to his own weakness.
That is why the US could arrest and strip search and Indian diplomat with impunity and deny visa to an elected Chief Minister of India while India made no protest.
Modi's revenge tells me that today a True Lion sits on India's SINGhSAN and no a circus ka Singh called MMS. And that helps me sleep a lot better.
Finally, US is a greedy entity and such slight matter little to their corporates. They will continue to do business with India as long as they can make money.
US foreign policy and defence policy is also not dependent on the personal relationship between obama and Modi. It is independent and will follow its own trajectory based on Geo-political realities.
Modi not caring much for the US does not translate as India not caring much for the US.
It only means US will have to try extra hard to convince India to trust it and work with the US. Meanwhile India will continue to seek all other alternatives to secure its interests.
China is no more likely to invade India than the US is
If anything China will fist invade Taiwan where it has some chance of a victory.