It’s not “genocide” but Netanyahu’s attempt to use Hamas gooney as a smokescreen to push out Palestinians predictably resulted in diplomatic blowback.
Even if the US defends him against ICC charges it will push many nations into the hands of China and Russia undermining US, and Israeli, interests globally. It will also bring unwanted negative attention to AIPAC influence in the US. And nearly everywhere Netanyahu goes moving forward he will face protesters accusing him, and by extension Israel, of being a war criminal.
The best thing for Israeli interests is to finally retire Netanyahu next election. He’s like Bush that made a mess of global goodwill towards America after 9/11. You don’t want Netanyahu to be the face of Israel moving forward. It’s not that everything he says and does is wrong but he has too many national and religious extremists unwilling to compromise in his government. And that inability to compromise is what lead to current situation with ICC. He also, irrationally, aligns himself with Christian Armageddon Jesus-is-coming fundy element of US politics because they blindly support him. Back in the 80s the US took this sophist approach to politics with the Saddam and the Taliban. It can work for a period but if you keep supporting crazies eventually the proverbial chicken comes home to roost.