Wellll, maybe not so difficult - look at the Muslims. If that religion isn't a hoax, I don't know what is.
Jesus' disciples on the other hand didn't have to take anything on faith - they knew - they were eye-witnesses - along with many others.
Yes, true believers will die for their cause. Not many though, will die for a known hoax.
Keep in mind that blowing yourself up doesn't take any more courage than holding a gun to your head and pulling the trigger - and the death is instantaneous.
Imagine, being the proponent of a hoax - as Jesus' followers must have been, and holding to the hoax for years - knowing it to be a hoax. No real reward - just suffering, torture, and gruesome death.
And you know, if there were only a few of them that hung on - living the lie - you could excuse them as fanatics. But for the whole group to hold on till the bitter end - eh, a hoax? I don't buy it...