The main reasons is that they were inspired by their leaders to fight. The leaders often invoked supernatural intervention such as magic,witch craft, or ancestral spirits. example is the maji maji rebellion where the leader inspired the natives that they would be protected by the water concoction. Another reason is that they were bitter and were often not afraid of death. They had already lost their dignity and had nothing to loss in their death. The third reason is that they were oblivious of the mighty power of the weapons.
It was Booker T. Washington, I believe.
Secretary of state I believe, but don't take my word for it. Hope this helps!!!
It was during World War 2 and it intensified during the Vietnam War