re: Has Israel ever suffered negative repercussions for civilian deaths?

Gaza is the most densely populated real estate on the planet, which means that it's impossible for Hamas to get far away from civilians. Additionally, Israel doesn't have the stomach for military casualties, even when confronted with an enemy that's willing to fight them far away from civilians. The proof of this is the 2006 Israel-Hezbollah War. Hezbollah evacuated its civilians to northern Lebanon away from the Israeli border and dug in their heels in southern Lebanon, and dared the IDF to come and get them. But after Hezbollah destroyed an entire column of Israeli armor, Israel retreated and started bombing civilians in northern Lebanon from the sky, despite the fact that they knew the bulk of Hezbollah's army was in southern Lebanon.

EDIT: Back in the day, the IDF was probably one of the toughest militaries on the planet, but in 2014, they're only good at killing 11-year-old rock throwers.