Netanyahu's government has (correctly) assumed that the pipeline of weapons and money from the US isn't likely to be interrupted by international opinion. They also assume (probably* correctly) that no amount of international outrage is doing to result in armed intervention. They see a clear path to annexation of the Strip and massive reduction in the Palestinian population there (one way or another).

A measured and reasonable response to the Hamas attacks would have garnered sympathy and approval from all but the most anti-Israel nations. But that approval wasn't going to net Israel that territory and reduction of a population that will never be anything but their sworn enemies. So they made a cold, calculated decision to take the course of action we've seen.

* the wildcard element in this calculation is that American pipeline actually being interrupted...not by international opinion but by internal civil war, a once-unthinkable contingency that's now thinkable AF