The fact is that the exercises were a signal, not so much to Pakistan, but to India. We want to strengthen our ties with that country and joint military exercises are a way to reinforce the fact that the respective militaries are friendly with each other. It's just possible that they might have to cooperate on the battlefield someday.
This author assumes that it would be on the battlefield against Pakistan, I think. That's certainly not going to be the case. US policy is to be allies with both Pakistan and India despite how much they may hate each other. That drives both countries absolutely nuts, but when it comes their stormy relationship, "nuts" is the norm.