If the West were trying to destabilize India I suspect it would be incredibly easy to achieve, which is exactly why there is that defensiveness and hitting at shadows. But the West isn't because India has long been a useful counter to regional powers.
What is absolutely true is that the Modi government is spectacularly corrupt. Every opponent of Modi is a "terrorist" -- even opponents in government. The government is falling further and further down the well towards fascism, all while proud Indians convince themselves that everyone else is actually the problem.
This is a common tendency for many Americans, read 10 uni-dimensional articles in your favorite newspaper on some topic, do not bother to read any history on said topic, then come to strong opinions and bully people who see things differently. Maybe it is you who should put down the "propaganda pipe" and consider this issue for the complicated nuanced thing it is.
The real issue is they wanted to kill someone who wasn't a criminal. Which, ultimately, is just plain old homicide.
When has germany deployed assassination?