It's flagrantly ridiculous, and easy to refute.

First, note that the speech was made to the Nasser-era Egyptian parliament.

He blames Israel for a ludicrous claim of Arabs having to spend on their military (to make good the threat to destroy Israel, I suppose). 

No doubt the so-called refugees can join the ethnic Germans of East Prussia, the Sudentenland, the former Yugoslavia as the victims of the losing side in history.  They're only two years apart in time.  Except, the vast majority ran off for an anticipated couple weeks - expecting their Arab colleagues to win the 1948 Israeli War of Independence and get rid of the Jews.  Well, too bad, the "refugees" slipped on banana peel of history and fell on their butts.  And their Arab brothers (except King Abdullah of Jordan) didn't welcome them in their own countries.

Incidentally, until the British Mandate in 1921 (and long thereafter) they weren't "Palestinians" but Arabs undifferentiated from other Arabs of the Ottoman Empire.