Look. this game can be played forever. There are many occupied lands throughout the world. Some occupied by Muslim countries as well. Why is it only the Israeli occupied land that is in question? What about Cypress? What about Kurdistan? How about Kasmir? Or does the word "illegal" only matter when it refers to Israel?
Ask the UN about that. Read all the documents regarding this case in order to understand the roots of the conflict and the difference between this case and the other cases you have mentioned. It's not as simple as you think.