You're absolutely right, Russia is a vassal state to China. Or worse, they might now be a resource colony to solve any problem that china has with minerals, energy, fresh water, capital markets, etc.

India is currently run by emboldened Hindu nationalists and they always like being on the good end of an economic agreement, let's say. They have a long history of close relations with Russia, straddling the middle ground as a founding member of the Non-Aligned moement. China likes China, and ONLY China. If your interests intersect for a while, that's nice - but not the point.