Javafour, Trust me when I tell you that I am anti-zionist but certainly not anti-semitic in any way.
To put the Palestinian Conflict in context, consider the fact that in 1914 the Jews made up 6% of the population of Palestine -- the marority were Muslems and a small number were Christians. By 1923 they were 12% of the population and they owned 3% of the land. By 1945 they were 31% of the population and they only owned 6% of the land.
They couldn't get the land legally, so they kept it when the opportunity arose.
Going back, throughout British rule preferential treatment was given to the Jews in many ways... including giving them equal representation even though they were clearly a minority. Also throughout British Rule (and remember that the Brits controlled the borders) vast numbers of illegal immegrants were allowed to enter and settle into the area despite the numbers set out by the League of Nations. There was also a considerable armed Jewish force (not surprising given their recent history in Europe) as well as what would be considered today as terrorist organizations.
What right did the League of Nations have in the first place to make the Balforer Declaration and displace the previous inhabitants?
In any case, as you stated during the war of 1948 over 700,000 Palestinians fled their homes. The Israelies did not allow them to return and kept their land. Thus we have the basis for the dispute.
Their is no recognized Law of Conquest as such, but I fully recognize it as a reality of History. At the time though it would have been contrary to the League of Nations and to civilized behaviour in general.
As you know, since 1948 both sides have done terrible things to each other. There are plenty of UN resolutions condemning the actions of both sides. Buldozing towns, erecting settlements on disputed territory, targeting civilians (both sides have done this - although Israel has done it much less often). Google them up yourself if you want specifics.