That is an interesting question Spock. Do you have an answer?
It certainly was not a lack of courage or willingness to die if they could take a few Nazis with them, at least not near end of the war when all knew what Hilter was doing to solve the "Jewish problem."
For example in the Warsaw getho up rising there were about 10 men for every gun they had at the start. They charged some German sand-bag circles with machine guns that were at major street intersection in a single file line with the gun held by the lead man. When he was killed, the numer two man got the gun to advance a few meters more. That and timing the first attacks well (Germans sleeping - not expecting any such craziness from the "sub-human Jewish scum") allowed them to capture machine guns, small arms, and even three tanks. Better armed, they held large part of the city for about a month, Expecting the Soviet army, which was then just on the other side of river (I forget its name) east of Warsaw to cross and re-inforce them.
Stalin did not want the Jews (or other Poles) to liberate Warsaw and have any post war claim to power. (He had other plans for Poland.) So, he forbid any of the troops to cross the river. After about two weeks of waiting for the order to cross, some Jews serving in the Soviet Army ceased two boats and began to cross, disobeying the order to stand pat on the East bank of the river. They did not make it across. The soviet artillery sank their stolen boats.
I know of no greater exhibiton of premeditated actions requiring organized courage by hundereds willing to die, knowing most would, than how the Warsaw Jews got the weapons to hold about half of Warsaw for a month. (The Warsaw resistance was not all Jews - Doubt if anyone knows what fraction were, but I bet at least half were.) Hitler was so outraged by this, that he actually pulled troops from the Western front to teach the occupied lands a lesson by destroying Warsaw. (Although the resistance failed, it was not without effect on the war.) The US and or English wanted to air-drop weapons and other supplies, but the round trip was too far, so they repeatedly during that month asked for permission from "ally" Stain to land in territory under Soviet control and refuel for the return trip. Stalin refused - he had other plans for Poland.
Again, It is a good question. Do you have an answer?