T. I. T. = "This is Thailand" and rural Thailand at that.
N.J. is thinking in terms of Western culture and not Thai.
Firstly - this is NOT the rainy season, that starts at the end of July and goes on until October. In the rainy season it is steady rain for many hours per day - it causes flooding, and the caves will flood then, but it does not cause flash floods as happened here. I live approx 80 miles away and my garden could do with some rain
The flash floods that caught out the children were caused by one week of violent thunderstorms that are normally localised. In June normally there would be no problems.
Education in rural society is not the same as the cities. Kids are taught subjects parrot fashion and are not taught to think for themselves. There is a general lack of "common sense" compared to Western Society or urban Thais.
Thais believe in karma and if it is your time, then that's it. Hence they take stupid risks with life with no fear. Religion again has a lot to answer for. Every day you see husband and wife, 2 or 3 kids all on the same motor-cycle and with a dog sitting on the riders lap and balancing on the handle-bars. The roads are good, but Thailand has one of the worst accident rates in the world, due to lack of common sense and "karma".
The coach I am sure would just be a "nice" person who has an interest in football and helps out the local team. He will not have any formal training as such, even I helped coach my local village kids team when I first moved over. At 25 he is more like a big brother to the kids than a teacher.
I am also sure he would not have taken them as far into the cave as that, but was instead driven deeper and deeper due to the flooding and the fact that the kids could not swim.
All the true facts will come out later, I am guessing also.....But it is not fair to cast aspersions on anyone until the true facts are known.