“Why is Egypt obligated to take 2 million Palestinians in this scenario when they’ve already said “no”?”
They’re not “palestinians”. They’re Egyptian Arabs and always have been.
L
There's so much genetic overlap between Israeli/Palestinian Arabs and non-Ashkenazi Jews (which I distinguish because Ashkenazis trace a lot of their genetic origins to Europe) that restricting Palestinians to pure Egyptian Arabic ancestry is just sheer nonsense.