With the discovery of dozens of terror tunnels reaching out to Israeli preschools I think I understand now why the three teens were kidnapped last month. Hamas, better than maybe anyone else, knows that their murderous militarism does not spring up overnight; it has to be cutlivated. Within the Gaza Hamas rules it's easy, but what about the world outside? So Hamas kidnapped the teens first. After some bargaining the teens would be returned, Hamas could declare a victory, and the world would be ready for the spectacle of 400 Jewish kindergartners stolen from their classrooms. But Hamas botched it and the teens were shot dead. The teens couldn't be paraded as a Hamas op, because when the kindergartners got kidnapped Israel would then have no expectation the children would or could be returned alive. So Hamas backtracked and denied everything. They probably judged that if they waited six months to a year everyone would forget about the teens and they could go forward with The Big Kidnapping as originally planned. (EoZ link)
Update, 8:15pm: Seems I'm mistaken; the tunnels under kindergartens were filled with explosives!