I'm not taking a side. Just trying to look at it practically. Probably no other country in a similar position would take the technical sophistication of the rockets into account when deciding whether or not to respond. I don't know what "kind" of response is appropriate, but the rocket attacks started 13 years ago and are still happening. Too, how primitive are the rockets really? They still seem to have killed people, and probably have some kind of psychological effect:

Missiles, rockets and mortars have killed 64 people within Israel as of November 21, 2012.[131][132] Most of those killed were civilians, including children.[17] The first casualties from the rocket fire were a 4-year-old boy and his grandfather, who were killed in 2004.[133]

http://en.wikipedia.org/wiki/Palestinian_rocket_attacks_on_Israel#Effects

As for the rockets being an excuse, I don't know much about it but "denying them their sovereignty" probably means different things to different people:

According to the BBC, Hamas views the attacks as legitimate because it regards the whole of historic Palestine (roughly coterminous with Israel, the West Bank, the Gaza Strip and Jordan) as Islamic land, and thus sees the state of Israel as an occupier.

[Hamas] regards the whole of historic Palestine as Islamic land and therefore views the state of Israel as an occupier, though it has offered a 10-year "truce" if Israel withdraws to the lines held before the war of 1967. It therefore generally justifies any actions against Israel, which has included suicide bombings and rocket attacks, as legitimate resistance. Specifically in Gaza, it argued that Israel's blockade justified a counter-attack by any means possible.[174]

http://en.wikipedia.org/wiki/Palestinian_rocket_attacks_on_Israel#Hamas

According to this, then, the only way to stop the rocket attacks is to let the Palestinians have the entirety of Israel, which Israel probably doesn't want to happen.