Of course it matters! You've identified a barbaric act. But you think the act exists on its own, some kind of peculiarity in a vacuum.
For years I was also like this. There's a very real, very honest character trait that gets us to try and "restore the balance". We want to justify (or condemn) each side to even the score.
Israel does not want genocide and it won't commit one. But it will ensure its borders from the threat that not only doesn't see the country as legitimate, but wants to see it vaporized.
There is room to criticize *vast* grievances by Israel and its governments. But the fundamental fight going on here is not a matter of "both sides have done wrong."