Explain to me like I'm 5, how a nation capable of such propaganda to install bombs in communication devices, hacked to be bought by leaders of terrorist organizations, capable of bombing the leader of Iran did NOT know about this attack? And if they did know, didn't do anything to prepare for it?
When you get a bit older you will realize that just because someone does amazing things doesn’t mean they are omnipotent and omniscient.
Also, there was a strong political will to try a peaceful approach to Gaza (with thousands of Gazans coming in to Israel for work every day), and with the belief that Hamas wants a peaceful approach as well.
Hamas is planning further attacks now, what do you suggest Israel do about it?