Not all of Israel. Israeli Prime Minister Benjamin Netanyahu has said he will obliterate Hamas. But undoubtedly hundred if not thousands of civilians will now be killed.
I’m not sure what Hamas thought the end game if this would be? What have the Iranians convinced them of? This was a sophisticated operation, outside help was given for definite.
I’m not sure it’s possible to rationalise with dehumanised terrorists, neither am I sure what the end game will be, but I just can’t understand what Hamas expected if not a total war/strikes from Israel in retaliation.