There are three moral standards used in the world: one, the strictest, for Israel, one, an average one, for most of the rest of the world, and one, the most lenient, for Arabs and/or Muslims.
The reason Israel is held to a different standard, higher than the rest of the world, is that it is the Jewish nation. We have here a mixture of "blame Israel first" antisemitism, by some people, and "after all the Jews suffered, they must be more moral than everybody else" well-meaning, but misguided, demand for higher moral standards.
The reason Hamas is held to a different, lower, standard than the rest of the world, is that they are Muslims (in general) and Arabs (in particular). Here, we have a mixture of "well, what can you expect from such savages? No point making a fuss about it" outright racism, and "well, the poor dears suffered colonialism, so they have no choice but to act savagely..." well meaning, but misguided, demand for lower moral standards.
This is unfair to the Jews, as it holds them to a higher moral standard that cannot possibly be met, and then blames them for it. But it is downight degrading and racist towards the Arab-Muslims, since they are presumed to be not fully human, not creatures who could be expected to act in a civilized or non-violent manner, it's only a disagreement about whether they are such by nature, or due to colonialism.
P.S
If the Arab-Muslims really couldn't act differently, no choice remains but to kill them or isolate them all from the rest of the world, for the same reason we isolate and even kill violent animals. The violent animal might have very good reason, due to mistreatment, to be violent; but since it cannot act differently, the world must be protected from it.
