Lofty even-handedness was not my intention, I have a definite side in this conflict because it personally affects me. I'm not unbiased and make no claim to be. I live in Israel and I'm scared of how this will end because I have skin in the game.
It doesn't matter to me who hit the hospital because I don't believe it was intentional. That's not to say the deaths don't matter, they do, and we should mourn them. And that's not to say that blame for the overall war doesn't matter, it does, I don't mean to say that we can't know anything and I'm not offering some bland hope for a ceasefire and end of suffering for all sides.
I'm saying that I don't believe figuring out whose errant projectile is responsible for this particular tragedy materially changes how I feel about the war[0].
Can I prove that it wasn't intentional? No, I can't. But I consider it much more likely than the claim that it was intentional. The Israeli claim is that it was an Islamic Jihad mistake, they're not arguing it was intentional. I don't know if Hamas claims Israeli did it intentionally or by accident, but it is entirely against Israel's interest to hit it intentionally and I see no reason they'd kick the ball into their own goal so spectacularly. Mistakes happen. War is terrible. And yes, this war includes a lot of war crimes.
[0] If eventually we find actual evidence that this was an intentional strike by the Israeli military, I will retract my position and express shock and horror at my government. I already express my anger at my more extreme, fundamentalist countrymen for their actions and statements that I consider to be immoral. The fact that they're on my team does not spare them from my wrath, on the contrary, I get more angry at them for the damage they do than I do at the extremists on the other side.