Apparently, almost all boys in Thailand spend some time as Buddhist monks. These boys will spend a matter of weeks as monks, not a lifetime.
A newspaper story I read, said that the boys went into the cave, and the coach reluctantly followed them. My conclusion is that the boys went into the cave because kids will be kids. The coach followed in an attempt to ensure their safety, but that did not work very well.
But now, they are safe, and there is no reason to judge anyone.