Answer: Because its not Israel's problem or responsibility. Contrary to popular revisionist myth we did not expel these people and thus we did not create this problem. Let the Arab petrol dollars "compensate" these professional refugees. Also, why don't you focus your examination on the Arab countries which force these "refugees" into camps, refuses to permit them to own land and/or acquire citizenship?
Colombia recalls ambassador to Venezuela amid border crisis (Reuters)
from the article: Palestinian refugees are a threat to Israel's existence