That is absolute bullshit. What Israel are doing can be justified because Hamas fired a few shells into neighbouring 'Jewish' land?
Whats happening in Gaza is genocide and part of the worst war crimes committed since the world war. The land Hamas are firing on use to be Palestinian land until the peaceful people where shot tortuned and burned from their homes, everything bulldozed and these Jewish settlements were created.. All in the name of these Zionist Jews 'devine right' to own the land.
Now 1.5 million people live behind a wall guarded by Israeli military in appalling conditions. Back a group of people into a corner like that and you are eventually going to see them hit back.
"When Israelis in the occupied territories now claim that they have to defend themselves, they are defending themselves in the sense that any military occupier has to defend itself against the population they are crushing... You can't defend yourself when you're militarily occupying someone else's land. That's not defense. Call it what you like, it's not defense."
~ Noam Chomsky
You might want to check your history Richie, Go back more then 100 years, try a few thousand. If there is any group of people who have a legitimate claim to those lands it is the Jews.