#1 it was unreasonable as it was the beginning of the larger plan that had been clearly laid out. It was nothing but an excuse.
#2 However unjust the peace was to that terrible war - borderlands had gone back and forth between nation state form all of European history. If a generation or two had gone by - maybe the sorting out of countries in Europe by lingustic or cultural groups would have happened by more peaceful means..
#3 if this was an excuse and a reason to start a nationalistic war - the odds of failure were too great. Many German speaking communites in central Europe and eastern Europe were destroyed during and after the ensuing warfare and settlement.