Why do you think there was no large scale effort to resist?

A large scale effort to resist would have been impossible because the men were starving, sickly, weak, and cold to the bone. The prisoners are also frightened, you have to remember that even those capable of resisting knew how slim their chances were against guns and soldiers. Lastly, many of the younger men had older famimy members to look out for...... and for the most part they did look out for them.