A completely stable and peaceful region is very much NOT in the interest of Israeli right-wing politicians (currently in power) hell-bent on expanding illegal settlements. Israel is the only modern nation in the world without a fixed border. This can only be maintained by denying Palestine statehood, and the only moral way to do that is by selling this image of "our savage, uncivilized neighbors will destroy us if we grant them statehood. We're in an extraordinary circumstance, so that's why we're taking the extraordinary measure of denying millions of people their human rights for 70 years."
Btw, 2014 Gaza war killed 5 Israeli civilians vs around 1500 Palestinian civilians (UN). It amazes me how Israel still manages to play the victim card in the western world.
Of course there were fewer Israeli casualties. Israel took the fight to Hamas for the express purpose of protecting Israeli lives. Safeguarding their own citizenry is the primary objective of any nation’s military, and Israel did that by fighting Hamas on their home turf (as opposed to inviting Hamas to fight inside Israel).
I guess it was an honest mistake on your part, though there are too many people out there with "all Palestinian are terrorist" belief.
I'm also assuming that the US, IL, and SA are pretty interested in regional stability if only because stability favors their own interests.
You have a few implicit assumptions of your own:
1. Keeping Iran in check "destabalizes the region" (and the corollary, that Iran's objective is stability in the region)
How can you believe this in light of Iran's pretty explicit intent to wipe out Israel? Are Iranian officials merely posturing benignly?
2. The US, IL, SA objective is "systematically killing tens or hundreds of thousands of lives and waging wars in the region" (and not to stabilize the region)
Of course, these countries aren't "systematically killing" anyone. You can criticize them for their actions, but they haven't been "systematically killing" anybody, nor expressed interest in the same.
3. There is a dichotomy between Iran killing tens or hundreds of thousands and the US/IL/SA killing tens or hundreds of thousands (i.e., if we prevent Iran from killing tens or hundreds of thousands then we implicitly allow its adversaries to kill tens or hundreds of thousands)
Of course, there is no such dichotomy. Thwarting Iran's nuclear program and stabilizing the region are two sides of the same coin.