This is not complicated at all like Michael Brooks says. RIP Michael. Imagine you had Jewish refugees in Gaza and West Bank and an Arabic government in Jerusalem. Imagine this Arabic government bombing Jewish citizens indiscriminately in Gaza and enacting an embargo whereby provisions would be blocked from entering Jewish Gaza and in the West Bank Arabic settlers uprooting Jewish citizens from their homes and security forces terrorizing them. How do you think the world would react then?
Imagine if Mexico was lobbing rockets into Texas or California. Or if Canada was firing into Minnesota, Montana, New York, et al. The US would be all over them.
As for your question about how the world would react: the world would probably do "not much" other than send terse diplomatic messages. Quite similar to our current reaction.
All multicultural societies are fucked up and fascist.
Quite a broad statement and not really true.
Some factions in multicultural societies are fucked up and fascist. Everyone needs an enemy - race, religion, gender, sex orientation, et al. Monocultural societies don't work very well.
All of this arises from an imbalance of power. Israel has the power. The Palestinians do not. The Palestinians should be upset with Hamas's supporter Iran.