Why were people confused by the actions of the himalayan guides?

From the text:

Days later—after six bodies had been found, and after surgeons had amputated the right hand of my teammate Beck Weathers—people would ask why, if the weather had begun to get worse, had climbers on the upper mountain not seen the signs of coming disaster? Why did experienced Himalayan guides keep moving upward, leading a group of amateurs, each of whom had paid as much as $65,000 to be taken safely up Everest, into an apparent death trap?