What would you say about dividing the regiments in the Indian army on the basis of their castes then!? Sikh regiment, Jat, Maratha, Rajput etc.? The ones who designed these knew that it worked out this way in the real world than bunching people haphazardly. Same is with the states. What would be the unifying factor if you were to draw some horizontal and vertical lines on the map and think the same exists on the ground!? Taking it to a personal level, would you tend to move with a group which speaks your language, than one which predominantly speaks a different language? Same will be the case with villages/towns and cities..
