Israel's current attack on Gaza is aimed at forestalling an ever more successful microwar waged by Hamas. Its rockets were inaccurate and most seem to have fallen uselessly in the desert. But they did do some property damage and killed 15 Israelis over 8 years, and they also inflicted psychological blows on the fragile Israeli psyche. The Israeli leadership saw a danger that Hamas would become ever better entrenched, organically, in Gaza society and gain all the advantages such a social penetration offers, and that monetary aid from Iran and explosives smuggling through tunnels from the Egyptian Sinai would allow them eventually to wage a truly effective micro-war.
The Israeli leadership knew that it could not reply to Hamas's microwar without engaging in total war on the Gaza population, and that this step would be unpopular with the world's publics. But the Israeli leadership has successfully thumbed its nose and world public opinion so often and so successfully that this sort of consideration does not even enter into their practical calculations (except to the extent that they are careful to do a lot of propaganda for their war effort). Their estimation that they will suffer no practical bad consequences of attacks on civilians is certainly correct in the short to medium term.