Why do Israelis bomb the holy crap out of Gaza in response to Hamas rockets, but only shrug their shoulders when Hezbollah fires rockets into Northern Israel?
The answer is that Hezbollah has weapons which can do serious damage to the Israeli war machine. In the invasion of South Lebanon the Israelis came face to face with guided missiles. One of their naval warships was sunk by such a missile. Since the defeat of the Israelis in Lebanon Hezbollah has re-armed and probably now has Russian made anti-tank and surface to air guided missiles. Any attempt by Israel to attack South Lebanon or Hezabollah will result in the destruction of F-16s, Apache attack helicopters and tanks. All of which will be broadcast on YouTube.
The real issue in South Lebanon is why Hezbollah is not launching more rockets and stronger and more accurate missiles on Israel. There probably is some kind of deal between Israel and Hezbollah. How long such a deal can last is the question.