Here's why the cave is flooded:
As you see, late June was a heavy rain period, and the beginning of July shows a bit of a lull on the rainfall, [which won't last long, for sure.] This is why it became imperative to move the boys now, rather than wait. With the pumps getting a lot of the rainwater out of the cave, there was no time like the present.
As for the coach, it has been made fairly clear in the Thai press that he took the boys into the closed areas of the cave to 'wake up' the 'spirits' of the cave. Local lore says that this would give competitors more power to win their next contest. This information came from the several other boys who did not enter the cave with them, for whatever reason. Those boys went home, while their mates ventured into the cave.
The superstitions here often take precedence over reason; and this time the thinking cost someone his life, as well as put others in danger.
I told my wife, who is a clever woman, that I thought the coach was extremely irresponsible. Her counter was, "But he took care of them in the cave. They could not have done it by themselves. If he hadn't been there, they probably would have been dead by now."
To which I said, of course, that without him they wouldn't have entered in the first place. She remained unconvinced of his culpability until I told her why he allegedly took them in. Then, she kind of understood how stupid it was.
The expats here have a saying. When trying to understand the locals, 'don't confuse the issues with logic.'