The US has a problem where left-wing activists can commit political violence and get away with it. There was an old Jewish man killed with a megaphone a few days ago. The killer will likely get away with it. That a problem for the USA and other Western countries, and isn't really Israel's problem.
It's not a logical argument. "Israel's government did something bad. Therefore, it's open season to assault Jews who don't live in Israel." If anything, that makes a stronger logical argument for Israel's existence, as a safe country for Jews. It also would make Israel's government stronger as more Jews are forced to flee there for their own safety.
Most Western countries are already experiencing maximum violence against Jews. It's hard to imagine it getting worse. The criminals are already doing the maximum of what they think they can get away with.
I don't see violence against non-Israel Jews getting much worse, if Israel genocides Gaza. We're already at peak Nazi. In just a few years, the extreme left has flipped from "Punch a Nazi!" to "Punch a Jew!"
Suppose you have two groups of people. Group A are logical and rational. Group B are religious fanatics who teach their followers to have as many children as possible and murder members of Group A. Group B also teaches their followers that, when they're in a country controlled by Group A, to obey and pretend to be model citizens until they're a majority, at which point they have a coup and slaughter Group A.
If Group A adopts a policy of religious freedom for Group B, allows Group B to move to their countries, adopts a policy of responsible families of 2-3 children each, and adopts a policy that everyone gets enough food and nobody dies a violent death, that just guarantees that Group B will take over eventually. If Group A also follows democracy, that means Group B will just make their religion the law once they're a majority.
The only way that Group A can survive without being overrun by Group B is if they periodically kill a huge chunk of Group B. If Group A refuses to do this, they only guarantee their own demise eventually. The only other way Group A can survive is if they ruthlessly control their territory and forbid Group B from entering.
If you follow logic, you unfortunately are sometimes forced to kill an enemy who swears they will kill you once they have the opportunity. If you follow emotions and ignore logic, then you're just guaranteeing your own demise eventually.