To be fair to Israel, they've given Hamas every opportunity to stop, including the whole creation of the Gaza strip, and yet they keep firing rockets at Israeli cities, hiding behind civilians and hoping that the International community will bully Israel into giving things up. Honestly, I don't blame Israel in the slightest and, although there are plenty of deaths which probably could be avoided, if they were just out to kill people, they wouldn't bother with the whole roof knocking, trying to get civilians to evacuate in 3 different ways etc.
While Israel isn't necessarily in the right, their targets are valid, having missiles under etc, whereas Hamas just spams rockets at cities with no military relevance. To be honest I'm sort of surprised the International community hasn't done more against Hamas, but I suppose people just look at numbers killed, without realising the reasons behind the numbers.