Any demand to resettle refugees within Israel undermines Israel as a state for the Jewish people
He is absolutely right.
And denying the right of return of those illegally displaced is, in itself, a form of Jewish racial supremacy, in particular when combined with the equally racist right of "return" for any and all Jews worldwide (nevermind that they never lived in the putative place of "return").
Israel is a state of Jewish racists, of the worst most arrogant and unapologietic Jewish supremacists and, as such, it has no "right" to exist whatsoever. Such a racist state is an abomination. Period.
Therefore, and *by definition*, anybody who in any way aids, abets or even approves of the "right" of such a racist state to exist in its current racist form makes himself an accomplice to war crimes, crimes against humanity, crimes of aggression, colonialism, imperialism and massive and grevious human right violations.
Lastly, racism, any racism, denies our common humanity and the common brotherhood of all men. It is therefore also a crime against God, our Creator.