Desmond Tutu views were incredibly consistant and technical, rather than emotional. Policy of Israel is driven by the need to maintain a Jewish majority franchise, should not need to explain why, however the simple demographics of the Arabs would quickly create Arab majority in Israel if Israel were to acknowlege soverentiy over the occupied territories or even permit the return of refugees.
An outcome like the above is of course clearly completely unacceptble, locally and in the west.
However Israel cannot allow even those territories to become independant because that would require giving up security control, control over valuable land and other natural resources like water. No nation gives away its territory easily!
So current status quo with the territories must be maintained!