The case was actually a quadruple-bogey. It asserted questionable jurisdiction, against a nation that had been subjected to unilateral armed aggression by proxies of a peer power (Iran) at a time when the EU states were leaning hard on the U.S. to defend them from armed aggression from another armed foe. I’d add a fifth major shortcoming— popular condemnation was a preferred weapon of Israel’s foe, forcing unpopular actions and isolating Israel clearly was a big part of the strategy when they invaded Israel and kicked off this round of violence.

So, yes, going against the U.S. was predictably an issue, but all the other unremediated shortcomings were what put the ICC’s legitimacy and ability to function in play.