So why does the whole universe think it belongs to them?
Of course not. I said nothing of the sort.
It describes a messiah that will reign over them [Hebrews] as a people, totally concordant with their [Hebrews] worldview.
As far as the Tanakh I agree.
Outside of a Jewish framework, I'm not sure why everyone else is so bothered.
Bothered? The main problems are the two fold extremes: (1) The Jewish perspective based on the Tanakh. is that this all there is in the human Divine relationship with God. through Revelation.
(2) Christianity interprets the Tanakh as ONLY the only interpretation of the Messiah as referring Jesus Christ and the succession prophetic inheritance of the lineage of the prophets and the Messiah for the universal Salvation of humanity.
I simply objectively view the Tanakh as the Hebrew historical narrative of their tribal history and beliefs.
I believe in a universal God that goes beyond the context of the individual history and culture of every religion in the the context of their own history.
I believe Judaism has the same problem as all ancient religions, and that is that they only acknowledge their own spiritual relationship with the 'Source' some call God(s) at the exclusion of other beliefs in a relationship with the Divine.