But many "de jure" war crimes are, actually, quite justifiable when they are effective methods to win a war and not just senseless cruelty.
I am sure that after the war crimes HAMAS committed, it is very tempting to state that certain war crimes by Israel should be all fine and acceptable for the time being, but that is an extremely slippery slope. Slippery with the blood of innocent people.
But sure, point taken, when you are equal or smaller in power it might be tempting to cut corners on human rights to reach military victory. It is also a risk. Ukraine's success greatly depends on continued support by their allies and popular support in those countries. News of serious war crimes would not help that cause and it looks like it will be a long war, where support will be needed for a long time.
But now for the situation in the middle east. If the military force of one side is many, many times that of the other, there should be a higher expectation for that side to keep the moral high ground. Israel is at no risk of losing this war if they at least attempt to respect human rights, but there is certainly risk if they don't.
Arab countries might in general be indifferent to Israel now, compared to the seventies, but if israel invades it's neighbours, or just goes on a killing spree, this indifference to what Israel is doing might well change and we could be back in a far worse situation.
And with that I've not even discussed the human cost of war crimes, which should be the very first and most important consideration. It's just hard to look at the middle east and not become depressed. Currently the power on both sides of the conflict rests with people who are not interested at all in making things better, and thus it seems, it will only get worse.