They didn't level ANY city. Fuck, Lebanon should count its lucky stars that Israel isn't pissed off to just say 'fuck it' and raze the entire country to prove a point. 300 casualties in over a week is a fucking blessing after the shit they've put up with.
And as for Lebanon not doing anything, thats exactly the fucking point. They let Hezbollah control 50% of the country, including a few seats in the national government. Their inability to control the militants is why they're getting the shit bombed out of them.