There was a war, people fled and were expelled from their homes for various reasons, Jews lost their homes as well due to the war. Sometimes fleeing a conflict is the least bad option. I have grandparents that had to flee their homes due to living in a country that was on the losing side of a war, they never got their homes/land back. I would probably even be considered a refugee by the UNRWA definition of refugee used for Palestinians. After Israels independence most Jews living in Arab countries were also forced out of their homes/land, I don't see Jews trying to get their original homes back in those Arab countries either. We can't go back in time and fix all the historical wrongs in the world, we have to move forwards.