Starting with your point number 1: Yes, perhaps Zionists stress the Jewish connection to Israel. But that's what makes them Zionists in the first place. Zionism is the belief that the Jews should return to the land of Zion--Israel (in Latin, Palistine). And it is also true that there has existed a strong desire to return to Israel in the Jewish people from the begining. Leaving Egypt, one could argue, was about returning to the land of Israel. A little more concretely, I suggest you read the book of Lamentations. Lamentations is a poem about returning to Israel after the Babylonian exile. After reading passages such as "If I forget Jerusalem, I will forget my right hand," it is evident that a passionate desire to return to Israel is not a fabrication by modern Zionists, but rather an integral part of the identity of the Jew. You then proceed with a non sequitor. Why does the existance of other people living in the land of Israel lessen the Jewish tie to the land of Israel? Finally, the website that you link to is officially recognized to be anti-semetic, so don't count on impartial information from it.
I don't quite understand what you're getting at in your second point. Are you saying that the Palestinians have their own identity? I'm sure they do. It just isn't clear to me how that backs up your argument. I'm genuinely curious.
As for your first point number three, I don't see its validity. There was no such thing as a nation until the rise of nationalism--far after 700 C.E.
Next, in response to your second point number three, going into the Diaspora was not a choice for the Jews. They were forced out. Do they lose the right to return after being forcefully evicted?
Finally, we can argue about political theory all we want. The bottom line is that Israel exists. Even if you do not agree with its policies, you should not advocate for its destruction. Israel is a sovereign and democratic nation (not to mention a center of growth and innovation) and by virtue of existing, it deserves to exist as much as any other nation does.
Thank you for reading