Both the parties are to blame here. Killings can't be justified no matter who does it. Its has to stop, terrorizing civilians in large cities is as much a cowardly act as much sending F-16s to bomb a helpless crowd.
And that kills kids, and UN inspectors and civilians. And of course these rocket launchers are wrong too, needless to say their rockets kill kids and civilians too.
Ok, we're moving somewhere. If the F-16s didn't exist, the rockets would still kill all those children. But if the rockets didn't exist, the F-16s wouldn't kill any children! I think we just figured out the solution to the conflict!
Although you never hear about it in most Western media Gaza militants also claim their attacks are responses to IDF attacks. The current escalation started when IDF killed a mentally challenged man and than a kid in an incursion a week ago. You can read about the tit for tats that have been going on here http://electronicintifada.net/blogs/ali-abunimah/how-israel-...
To always blame the Gaza side as the aggressors and as terrorists is just to swallow IDF propaganda whole and uncritically.
The basic point, which you're overlooking, is that the Palestinian rockets are pretty crappy, and Israel has overwhelming military superiority - look at the casualty list from 2009: http://en.wikipedia.org/wiki/Casualties_of_the_Gaza_War