* The untenable position the Palestinians are in today stems at least in part to the results of the Six-Day War, wherein Egypt ultimately conceded its administration of Gaza --- in which Palestinians were not full Egyptians --- to Israel, and Jordan conceded the West Bank, which it had annexed after the Arab-Israeli war. That's what Rayiner was referring to upthread --- what happened "56 years ago" was the Six-Day War.
* The Six-Day War may have had multiple causes, and perhaps nobody's hands are clean in it, but it seems beyond dispute that the "preemptive" strike against Egypt was a response to months of military provocation by Syria and, especially, Egypt, both of whom had mobilized on Israel's border, arranged the expulsion of peacekeepers, violated Israeli airspace, and blockaded the Gulf of Aqaba, an act Nasser acknowledged made war inevitable.
* Had the Six-Day War (and then the Yom Kippur war, which was, like the Arab-Israeli war that preceded the Six-Day War, unquestionably a war of aggression by a coalition of Arab states against Israel) not happened, the cause of Palestine would be directed instead at/against Egypt and Jordan.
* "From the river to the sea" implies, among other things, the dispossession of Israeli Jewish people outside the West Bank and Gaza.