They purposely ignored warnings from both IDF intelligence soldiers and independent monitors so that they could let Hamas attack.
Therefore, having a reason to mount a full scale invasion of Gaza. The attack was needed to galvanize public opinion in Israel and the rest of the world.
However, this does not change the fact that Hamas are bloody savages. That they chose to attack civilians and commit atrocities not seen in the civilized world in a long time.
It would have been different IF Hamas had only attacked IDF bases across the border. IF they had only taken prisoner IDF soldiers. IF they had only killed IDF soldiers. No, they killed hundreds of innocent women and children. Many of them raped and killed in the most brutal means.
So, in a way Israeli Intelligence and Senior Political leaders just let Hamas be released to do as they do. Be the savages that they are. The difference is that the whole world was witness to it on a much larger scale.