Israel signed the Rome statue and has repeatedly violated specific orders from the ICJ to prevent genocide, so let's not pretend that this is somehow about a concern for international law.
Another great point! The US doesn't recognize the ICJ anymore after it was caught illegally planting mines in Nicaraguan harbors and lost in the ICJ. A verdict the US still has not complied with. Just more evidence that upholding international law isn't a priority for the US.