Israel is currently the US’ closest ‘ally’ in the Middle East. Not that Israel wouldn’t turn on the US in a heartbeat, but the US needs Israel to maintain force in the region. Add to that, Israel is Jewish. In light of events almost 100 years ago, it’s a bit problematic to criticise anything a group of Jewish people do.
The US can’t exactly come out and say anything that would be too disruptive to their relationship with Israel.