One is a country, one is an individual, to say that any individual is more important to the war than the United States is the literal definition of Great Man Theory (i.e. childish nonsense).
This is without getting into other considerations like how Netanyahu is a scapegoat for faux-progressives who want to deflect away from how this genocide has enthusiastic support from many powerful institutions within Israel. It is an Israeli project much more than Netanyahu's personal project.
P.S. Assassinating Putin wouldn't end the war in Ukraine either (nor would assassinating Zelensky or Biden)
I think people jump to "Read On Authority" to quickly, a behavior that amounts to scripture-quoting, but
chatgpt sucks and has demonstrated that again here. On Authority essentially argues that a socialist revolution 1: is itself a monumental exercise of authority and 2: requires authority to be protected when it exists in a world fundamentally hostile to it. There are some ancillary arguments about command structures, but overall it is written in opposition to anarchist dogmatism about "Authority" being an evil thing that must be discarded.
I'll let someone else unpack the "Stalinist Russia" part