I think you're misunderstanding what is meant by proportionality, then. Google "Law of Armed Conflict Proportionality". Basically, each individual attack cannot cause a disproportionate amount of collateral damage to non-military targets. So dropping bombs on a hospital that kill, say 10 Hamas fighters and 50 civilians, is disproportionate and wrong. This creates a problem when Hamas is using hospitals for military purposes alongside civilians seeking care... but it doesn't override the need for proportionality. It seems Israel doesn't care how many civilians they kill as long as they accomplish at least something militarily. That is how war crimes are committed.