But if you start giving a nation to every group who wants to be independant where do you stop? The Basques and ETA in Spain would like their independance too.
Also, what happens what the definition of independance of two terrorist groups conflicts, such as in Northern Ireland?
And surely there will be people living in the newly created nation who were happy with the previous arrangement, surely they are then marginalised.

I forsee a world of 1,000 nation states if this were done.