Yeah, India likes to talk big game and antagonize China and Indian nationalists are annoying, but it's doubtful that India would ever really interfere with China in a big way. Both of them have far too much to gain by knocking America off of their hegemonic perch. What I am surprised by, however, is that America is going on ahead with this. Surely this is a good opportunity for America to do a whole big song and dance about how they're cancelling this exercise because things are tense in Asia right now and playing up the whole angle about how America's doing what it can to maintain peace and China's being so aggressive and awful etc, etc, etc.
It seems like America needs someone to look over the shoulder of their diplomatic core as well. I wonder who'd pay me in better Shinano body pillows. The PRC or the US.
Meh I think for both US and China this "high altitude" exercise isn't meaningful and it was probably planned a long time ago. I could imagine its mostly just some US salesmen going over and showing India the US high altitude gear to wow them and some purchases. Then you'll hear jai hinds talk about how their new assembled in America (from Chinese components) thermoses and tents give them a big advantage.
If the exercise involves thousands of troops like the typical SCO or NATO exercises then there is a little more cause for concern but nowhere have I seen the number of troops involved here, so I can only conclude it is a small, goodwill type exercise like the ones China even do with US and Japan from time to time.
About canceling it, India will make a huge fuss if its canceled, while China doesn't really care what 2 sovereign nations do especially when it's on a tiny scale. Its hard to imagine the exercises incurring any wrath from China, and while Xi has the initiative now, he should also not overplay his hand by threatening every single thing US does, even when it's unrelated. That would just cause the perception of aggressor to switch over to China.
The capital gained by US misstep still needs to be invested intelligently. And grilling US over some irrelevant exercise with a BRICS member isn't it.