Sometimes the senior folks don't want to hear the negative news...or potential negative news.
Which I imagine in the intelligence world there's always something about to blow up somewhere. And when it doesn't, then it becomes a case of the boy who cried wolf.
I heard more explanations.
Israel (and US?) have extremely high tech radio & internet monitoring programs. They have the money & the management.
HAMAS waged a low tech strategy. There were low tech warnings. But there was no hi tech warnings not hi tech confirmation of the low tech warnings. So the warnings were ignored.