Hang on. We're always told that 750,000 were displaced in the Nakba. That means there are millions of Palestinians who are probably third or fourth generation who have never, ever, lived in the former Palestine territory. They were born in places like Jordan and Egypt but aren't allowed to be citizens, and their descendants may never be.
I said earlier in this thread that my great-grandparents came to the UK from Eastern Europe around 1900. I'm a third-generation British citizen, not a Russian refugee. My American daughter-in-law has a British passport alongside her US one because her father was born in London to parents who were American citizens living and working in the UK at the time of his birth.
Now here's an interesting example of how people can hold two entirely conflicting views at the same time without any form (in their minds) of irony.
People seeing that Arab refusal as somehow noble, yet criticise our own government for its treatment of migrants and refugees. Even if you're of clear Palestinian descent but have no desire to go back and would love to be a Jordanian citizen, you're still not allowed to be. You're effectively an outsider and always will be. So being a 'Palestinian' despite having lived all your life in another country, is like being a Jew in Nazi Germany, but with the 'Palestinian' tag replacing the yellow star.
The real reason Arab governments (bar Lebanon I think) deny citizenship to even third or fourth generation Palestinians is because if they do that, the problem goes away and they have no stick to beat Israel with. And that shows just how Arabs see Palestinians. They're only useful as refugees, not as human beings.