This latest flare up was ostensibly triggered by the murder of 3 students. The backlash from Israel has killed more than 600 Palestinians.
But surely Israel should be able to defend themselves from missile attacks?
Yes they should, and they do. They have a missile defence system, Iron Shield' which is highly effective. A third of missiles are intercepted, if their trajectory goes near any populated. Software detects which missiles will reach populated areas, and which will land harmlessly. The missiles are not 'smart' so the majority are misses anyway. Of the thousands of missiles that have been fired, the resulting casualties are very very low.
http://www.theguardian.com/world/2014/jul/09/iron-dome-gaza-israel-air-defence-missile
So yes, it is about proportionality. It seems that one Israeli death is punished by 200 Palestinian deaths.