Your quite wrong about Israel not being capable of stopping the rocket fire. You would have been right to say it did not. Israel could have completely destroyed Gaza, used as others have pointed out the Churchillian strategy of eliminating the problem. She didn't for a myriad of reasons. However, I'm quite sure that if renegade groups started up in Israel with a mission of killing as many Pals as possible, they would get nowhere and would be dealt with severely. The difference is one of degree. Hamas's approach to dealing with renegades is relaxed chastisement and finger wagging unless and until their leaders are threatened.
Seoul: North Korean leader Kim had his military chief executed (AP)
from the article: 'Israel will defend itself from Gaza rockets, regardless of Goldstone'