What you've just explained is the very reason why nationalistic ethno-states in general are a bad idea, because they obsess over this idea of tribalism, and the working class being compartmentalized and atomized in insular tribal communities hostile to those of other ethnicities or religions. This is the exact opposite thing to Communism which strives for a class-less, state-less society.

Marxists don't think Jews should have their 'own' nation-state. They don't think Palestinians or Arabs should either. Nationalistic chauvinism is antithetical to Marxism.

This business of picking one preferred ethnicity or religion over the other leads to all the chaos we're now witnessing. Despite all it's flaws, one idea the USA gets right is the Establishments Clause, which states that the government cannot declare any one religion to be official - at least domestically. Obviously, US foreign policy is an inconsistent mess in terms of what it backs on the global stage, because the US empire is ultimately driven by power and capitalistic profit as it's guiding principles.

Yes, the Soviet Union backed Arab Nationalism, largely as a response to The US backing Israel. At that point, the USSR had devolved under Stalin and was engaged in the same game of imperial brinkmanship as the USA.