Because multiple kids haven't collapsed on this coaches watch or at least it hasn't been reported.
So one dead student is what we'd consider acceptable?
If coach has 23 kids and only 1 collapsed, was this one kid asked to do something the other 22 were not?
Doesn't matter. By that logic if the coach had asked all 23 to do it and one died he'd be culpable. But if he asked all NOT to do it and the kid did it anyway then the coach is still responsible.
Were any of the other 22 kids near collapsing but didn't get to that point because this one collapse first and in turned everyone stopped doing what they were doing?
Immaterial.
Like others asked, did this 1 kid show signs that he was about to collapse but was ignored?
Immaterial.
One of the coaches talked about the increase in air conditioning and the decrease in the heat tolerance of the kids. 40 years ago AC in schools was unheard of, let alone in homes. Today it is everywhere.
Then he's an idiot and should be banned from coaching. Unless of course the human body is able to evolve in 40 years to something they were not in the previous 3 million.