That's not axiomatically true as its not always possible to know how many deaths will occur in any given operation. There's too many variables at play for that and too many things that can go wrong. All operations have risks.
Anyone who claims they don't or believe they don't are lying, ignorant or both.
There is a difference between international law on the legality of military operations and whether people die. The sad reality in every type of warfare is that innocent people WILL die.
If there was any way around that during war, we'd have found it by now. But there isn't.
Because of the fact the dead are still dead, it's better NOT to start wars.
Unfortunately for Israeli and Palestinian peoples, Hamas decided to start a new war on 7th October 2023 when there was no need to.
That's the cold, hard reality here. The Israel Defence Force wouldn't be operating inside Gaza since October 2023 if it wasn't for Hamas.
Indeed, the IDF pulling out of Gaza in 2005 enabled Hamas to develop their plans over a good period of time. As their leaders admitted, they went to a lot of effort to make Israel, the West and everyone else think they were happy to govern Gaza.
Like I said, it's better not to start wars.