In the current circumstances, the division of mass-governance (a state) is based on territorial boundaries. So if these 10 million and 1110 million have different discrete territorial area, they have the right for their own governance on their own territory and not over the others. If these are spread out (distributed), then the way out is through negotiation and not oppression by an armed force.
The army's role is at the territorial boundary, and that's also their place of action. If armed forces are in continued action for a long period, then that place becomes a territorial boundary.
If armed force fights with an armed opponent, then they are honored as fighters, however, if they fight with unarmed public, (e.g. like in India and Israel) then they act "gundas", enforced by few people in power.
What you are saying make sense however just in theory. First of all every nation think about their won interest first. Sometime you have to make harsh decision which may look unfair however if you understand the reasoning behind it, it may make sense.
The so called champions of democracy and human freedoms Greeks, Britains captured territories ( and are still holding) against people’s will. America’s drone attacks, attack on middle east and Afghanistan they all are unfair, undemocratic against people’s will. However they were strategic decisions.
If India leave Kashmir, do you think it will be good for them? No, Pak will capture it or share it with China. No one will leave those big water resources uncontrolled. Plus it is also a strategic location which provide access to Arabian sea (through Pak) and middle Asia.
We all share the pain of people in Kashmir however such decisions just cannot be based on emotions. In perfect world everyone has right to govern their own territory but alas it doesn’t happen. If Eagle won’t eat the rat, cat will.