1) If the land belongs to those who were there "first" then it undeniably belongs to the Jews. If you want to say "the Palestinians were there 'first'" you have to be convinced that Muslims are descendents of those that the Old Testament Jews killed in order to take Canaan. Since Muslims themselves trace their descent to Abraham's son Ishmael, this makes no sense. (And this is not a "God ordained it" argument, I'm an atheist. But I do believe the Bible has historical significance.)
2) The Jews didn't steal the land, they bought it rightfully.
3) The Arabs were offered statehood in 1948. They rejected it. Then they attacked Israel.
4) Not all Palestinians are refugees, about 1,000,000 have Israeli citizenship.
5) Those who are refugees have as much claim to Jordanian citizenship (more really) than to Israeli. But they don't want it and Jordan doesn't want them. Why? Why would they rather be refugees in Israel than citizens in Jordan?
1) If the land belongs to those who were there "first" then it undeniably belongs to the Jews.
I too am an atheist and I don't accept any 3000 year old claims of any kind by either side. While I have a sentimental attachment to my native Scotland, I have no claim to the place, even though my ancestors were expelled from there a mere 200 years ago. I would have no idea where to find my ancestral home and against who to claim a claim. As for Jews in Palestine, it is not even clear if these white Europeans have an ancestral home there. If they do, it is obvious that they have no idea on what piece of ground it might be found.
The Arabs lived in Palestine/Israel for many generations. They built houses, orchards, villages. It was their land. Many of the people whose land was stolen are still alive.
2) The Jews didn't steal the land, they bought it rightfully.
This statement is simply false. Most of Israel is land which was stolen from the Arabs. Less than 10% was actually paid for. And even this was obtained through the process of feudal clearances - ethnic cleansing. Jewish agencies would buy feudal holdings from the landlord and run the peasants off the land. The tension between Arab and Jew before partition was directly attributable to this process.
3) The Arabs were offered statehood in 1948. They rejected it.
The Arabs were told that their homeland would be partitioned. Jews represented one third of the population and owned about 7% of the land. Despite this, the Arabs were offered a state consisting of 43% of the area of Mandate Palestine. Wouldn't you reject this "offer"?
Then they attacked Israel.
In the months leading up to partition, Jewish terrorists cleared Arabs out of much of Palestine in a systematic attempt to obtain more of the land. When the British finally left, surrounding Arab states attacked. When the smoke finally cleared Israel consisted of 78% of the land and 700,000 Arabs were refugees. While there is fault on both sides, the facts are that the Arabs were offered a bad deal in the beginning and became refugees when they attempted to object.
Over the next 50 years, Israel has repeatedly ignored Arab attempts to reclaim the land stolen in 1948 or even to offer compensation. Unsurprisingly, this has caused some tension between Israelis and Arabs. In 1967, Israel used this tension as a pretext to invade and conquer the rest of Mandate Palestine. Since then, it has pursued a policy of state-supported colonization.
4) Not all Palestinians are refugees, about 1,000,000 have Israeli citizenship.
Who cares? Israeli treatment of those Arabs who have citizenship is decent (although not perfect). But the question is about the 4,000,000 who are refugees or who live under military rule.
5) Those who are refugees have as much claim to Jordanian citizenship (more really) than to Israeli. But they don't want it and Jordan doesn't want them. Why? Why would they rather be refugees in Israel than citizens in Jordan?
Wrong. The land they were expelled from was Isreal, not Jordan. The state which stole their land was Israel, not Jordan.