But world leaders, including the US, have turned a blind eye to these illegalities for decades. That deference needs to stop.

I suspect the only way to stop these illegal settlements and the willful murders of Palestinians in the West Bank and East Jerusalem is for individual countries to levy economic sanctions.

From Wikipedia:

“In 2004, an advisory opinion by the International Court of Justice concluded that Israel had breached its obligations under international law by establishing settlements in the West Bank, including East Jerusalem and that Israel cannot rely on a right of self-defence or on a state of necessity in order to preclude the wrongfulness of imposing a régime, which is contrary to international law. In its 2004 advisory opinion on the Legal Consequences of the Construction of a Wall in the Occupied Palestinian Territory it states, at paragraph 120, that Article 49(6) "prohibits not only deportations or forced transfers of population…but also any measures taken by an occupying Power in order to organize or encourage transfers of parts of its own population into the occupied territory." All 13 judges were unanimous on the point.[44] The Court also concluded that the Israeli régime violates the basic human rights of the Palestinians by impeding the liberty of movement of the inhabitants of the Occupied Palestinian Territory (with the exception of Israeli citizens) and their exercise of the right to work, to health, to education and to an adequate standard of living.[45][o]”