First, let's get some history straight. The state of Israel was NOT founded simply because of the Holcaust. The nations of the world may have finally voted in favor of the State in 1947 because of their own feelings of guilt and/or compassion in light of the Holocaust, but that was their issue, not the Jews'. The Jewish people had longed for, dreamed of, and prayed about returning to a reborn State of Israel for thousands of years, and the modern movement known as Zionism, was more than half a century old by the time the State of Israel was founded.
I don't know what you mean by "the Arabs", but if you are referring to the Palestinian people, they care because they too want a nation of their own. The fact that past events, especially the actions of other Arab states, may weaken their historic claims, actually does not matter. They are a distinct community and seek political self-determination, and why should that claim not be recognized?
The world should care for any number of reasons, not least of which is that what goes on in the Middle East effects us here in the US, that Israel is a valuable ally with a society very much like our own, and that when possible, we seek to nurture peaceful, democratic movements whereever they may be. While the real threats to the US arre not centered in the Israeli-Palestinian conflict, resolving it would strengthen our own strategic interests in the region.



