Why do people like to argue that changing the status quo would cause suffering as though the status quo is not itself causing plenty of suffering? Especially when the chaos "caused" by change is most often actually caused by violent opposition from those desperate to preserve the current state of things?
The disruption is usually not worth it once generations have built their lives and have built their homes based on an existing border regime.
Read about the India Pakistan partition. How would you feel if you have to leave behind everything you have and move to another country because someone decided it is so.
Again, in many cases this is an arrangement that's only about a hundred years old (with about six or seven decades of sovereignty) _and_ is clearly not working out for the people involved. Why do people talk as though they are immutable institutions from prehistoric times?
Plenty of people built their lives on the US being a British colony. Plenty of people built their lives on Austria and Germany being a single country. Plenty of people built their lives on the USSR being a single entity. I could go on and on listing examples. Why is everyone else allowed to naturally form their own national identities but recent (particularly African) colonies are supposed to suck it up and endure the empty ones forced on them?