I’m going to disagree, because this sort of argument becomes a tool legitimizing the killing of civilians.
No, it is not a tool for legitimizing the killing of civilians. It is recognizing the complicity of people who participate in the war (and in war crimes) who then
lose their protected status.
Every adult in the two apartments where the hostages were kept are actively participating in the war and committing war crimes. They are not protected civilians.
Every adult who attempted to thwart, block, or prevent the rescue of the hostages is actively participating in the war and committing war crimes. They are not protected civilians.
Every adult who participated in the captivity, movement, medical treatment, video-recording, or provision of necessities to the hostages is actively participating in the war and committing war crimes. Not protected.
Every adult who could reasonably have known that hostages were kept there, due to Hamas activity in the building, as example, is actively participating in the war and committing war crimes. Not protected.
Every adult who had no freaking idea what was going on right under their noses was deliberately put in the midst of a combat zone by virtue of the fact that hostages were being kept embedded within a densely-populated displaced persons camp. The responsibility for where the hostages were kept is solely on Hamas and/or the people of Gaza who chose to put them there. It is their decision, their choice. They need to take responsibility for it.
Israel can not create the circumstances in which it is obligated to fight. That is on Hamas.
200+ killed, yes? How many were actively participating, either in holding and keeping the hostages or in attempting to prevent the rescue? 50? 100? 200? How many were caught up in what I understand to be an extensive exchange of deadly fire in the middle of a crowded marketplace and two civilian residential complexes because Hamas put the hostages there?