The land in 1948 belonged to Israel as per the UN resolution.
The five arab countries lost more land because of their aggresive, and barbaric, push to wipe Israel from the map.
They were the aggresors, they have no moral right to cry about lost land after they were the ones who made the unprovoked attack.
Again, the UN cut up the Middle East like a cake without thinking of the consequences. Yes, that land is now Israel. However, just because it is Israel does not give a country a right to push out whomever they like for no good reason. That goes against what the UN stands for.
See what ignore people like you think is that Israel was that everything happened in '48! Not the case at all, long before that Israel had a de facto functioning government in the holy land!