Gandhi was killed by Nathuram Godse, who had a number of affiliations with right wing Hindu fundamentalist groups, but AFAIK, the actual assasination wasn't organized by anyone - it was Godse working alone. His political views are, of course, in line with Subhas Chandra Bose before him and the VHP/RSS of today.
As for the news article, I agree - seems to be presented as an amazing new discovery or something, when it's not. So some Indian soldiers deserted (a few hundred out of many thousands in the British Indian Army) to fight (in their minds) for their country's independence, figuring the British were never going to let India go. I don't agree with what they did, but I have the benefit of hindsight.
Given that their country was occupied by England, and Indians were essentially being forced to fight in a war that had nothing to do with them, I can't condemn them morally. It's not like they were mercenaries fighting for whoever paid them, and they were hardly traitors to their country - only to the British.
The Indian political leaders promised co-operation with the British in WW2 in return for independence and delivered magnificently on their promise (and eventually so did the British). Some of these soldiers obviously felt that wasn't the best way to go about independence. (And it is to be noted that even in that situation, the overwhelming majority of the British Indian Army fought heroically against the Nazis).
FWIW, India had no conscription. The Indian Army in WWII was the largest all-volunteer army in history.
once again, it wasn't a few hundred, it was thousands of troops. They also occupied other countries themselves (look at the pics from singapore and the Philippines). They fought in Europe and against the US. That has nothing to do with british colonization of India. Also remember, the British had promised to free india after the war (as they did).