I don't think that's necessarily accurate. The Nazi's conquered many countries without exterminating their population. As I understand it they only attempted to exterminate Jewish people, homosexuals, and the disabled.
Granted even that is deeply evil, but it doesn't mean that they would wipe out any given people group that they conquered.
They also planned on wiping out 100% of Latgallians, 85% of Poles, 85% of Lithuanians, 75% of Belarusians and large portions of most of the rest of Eastern Europe[1]. The groups you listed were some of their top priorities, but by no means where they intended to stop.
> The Nazi's conquered many countries without exterminating their population.
On top of Generalplan Ost the holocaust had 12 million victims, 5 million of whom were Slavs. The only reason why they aren't counted as genocide victims in the West is because it was not convenient to admit that during the cold war.
As a percentage of the population of the time it would have been similar to the British gassing 17 million Indians after starving another 45 million. And that would have been in three years of occupation, not a century and a half.
So yes, India was incredibly lucky to have the UK as their colonial overlord.
Granted even that is deeply evil, but it doesn't mean that they would wipe out any given people group that they conquered.