Sadly, Laura, you might as well ask why people consistently do other stupid things that place themselves and others in danger when they know better (texting and driving comes to mind). Even with heightened education on the dangers of AMS, a significant percentage of people will always adopt a "can't/won't happen to me or mine" attitude.
The frustrating thing to me is that so many of these incidents involve kids, many too young to really understand what altitude sickness is all about. Last year on Whitney I was shocked at how many children were descending with AMS symptoms, including one notorious case where the parents sent their child back down to Trail Camp with complete strangers while they continued to the summit. There are your Parents of the Year Award candidates . . .
I recall running into Brent N on the trail last year with his family, not far below the Windows. His son (12, I believe) was beginning to develop symptoms about a mile or so from the summit. There was no hesitation in Brent's mind - screw the summit and descend. No question about it. I felt badly for them, missing the summit with so little distance to go, but he made absolutely the right decision.
Less than 30 minutes later I had to make the same decision for the well-being of my 11 YO daughter, Bri, who really began to flag at 14,000 feet. No observable AMS symptoms, just moving really slow. Her diminished pace would have pushed our return over the snow chute at Trail Crest into a time of the day where icing became a concern. We talked it over with Ranger Rob (Crabtree) and decided discretion was the better part of valor. With the summit hut in sight, we turned around. Bri insisted she could go on, and was devastated by the decision my wife and I made to pull a 180 and return to Consultation Lake, but as parents the top priority has to be your child's welfare. Could Bri have made the last mile to the summit and returned safely over a somewhat icy snow chute without spikes? Very likely, but we weren't going to risk it.
People will continue to do stupid things in the mountains, but when you bring children along for a hike like Whitney it is incumbent on the parents to be educated and watchful. Unfortunately, there's no effective way to mandate that responsibility currently. Maybe Inyo should determine if any children are in a group when permits are issued, and if so place the group leader through a required uber-orientation.
