I think more than size, it is about the cultural/religious/historic identity of across a geographic area. If you look into the history of how many country borde

I think more than size, it is about the cultural/religious/historic identity of across a geographic area. If you look into the history of how many country borders were created (India-Pak, The creation of Iraq, the creation of Syria) etc. a lot of the historic distress caused between the people is because of differences in identity. If there is a strong shared identity between people across a large area, then it is relatively easier to understand concepts like "for the greater good" and empathizing with people as your own. Sadly, countries rarely are created as such, and are demarcated more along lines of conquest (which is a very weak signal of local culture, especially if the local civilisation has been around for 1000s of years but conguests happened 400 years ago) or even sometimes on what can only be described as kookoo political ideologies.