The only thing it proves is that war is ugly. War desentasizes you. There have never been a war in which there weren't incidents of people losing moral grounds. That however, isn't a problem for Hamas members who have never had any moral grounds to begin with.
While Israel itself is investigating and publishing testimonies, while Israel's army police is already investigating into these testimonies to check whether there were crimes committed and if were - Put those responsible on trial, Hamas members glorify and pay a reward for every killed Israeli civilian. After the recent operation, I even saw pictures of Palestinians parading on the streets with a bag with Israeli soldiers' body parts.
But hey - Why am I telling you this? You don't care, you're not here because you're some philantrop, you're here because you hate Israel/Jewish people.
In Gaza's fighting enviroment, every man, woman and child could be a potential assailant.
When you have 14 year old children strapped with bombs to them:
http://www.youtube.com/watch?v=eSMhuSgYKZA
And women who promise to kill Jews:
http://www.youtube.com/watch?v=PPU4UN03t7E&feature=related
Every person could be heading towards you to kill you.
The soldier was given an order to shoot anyone who enters a certain area. The woman entered that area and he was simply following an order. For all he knows - That woman could have been the one from the clip above and those kids could have had a bomb strapped around their chest. It's always a shame when civilians get killed, but that is war for you.
I, unlike you, prefer to focus on stopping war altogether instead of focusing on how bad war is. War is bad, every idiot knows that. What matters however is what led to it and who is responsible - Israel was forced to act after several hundreds of rockets shot in a short period. All the while, Israel repeatedly issues publics warnings and requests to the Hamas to stop the attacks or else Israel will have to act back.