OK, I am still finding this puzzling.
Why would Biden support Israel's right to defend itself, but not support Israel striking Iran's nuclear weapons development facilities?
Is the US concerned that such an Israeli strike alone might not be completely successful, and aggravate the Iranians to the point that they accelerate towards breakout.
At which point, the only power with the reach and mass (TLAMs and Bunker Busters) to rapidly stop Iran would be the United States.... thereby dragging it into direct conflict?