Based on what has been explained and based on what I have read, here is my understanding. Perhaps
@DinkleMouse can correct me if I am wrong somewhere:
a) It needs to be determined if there are military installations and infrastructure in said location. For example, a hospital where Hamas fighters along with civilians are getting treatment is not a site that qualifies as being used for military purposes.
b) If there are military installations/infrastructure and an active attack is being launched from there, then that site is fair game, even if civilians are there, because it counts as self-defense.
c) If there are military installations/infrastructure with no active attacks being launched, but has civilians near by, then it needs to be determined if the military value of taking down that target, exceeds the civilian lives lost. For example, in my opinion, taking down a battery of rocket launchers that are currently not active, and killing 500 people in the process, is a war crime as the value obtained does not exceed the lives lost.
d) If there are Hamas fighters and commanders in a civilian location, like a refugee camp, then again, the value obtained by killing those Hamas guys should be measured against the civilian lives lost. I think DM gave an example of Hitler being admitted to a hospital with a 1000 other civilians. If killing Hitler would have ended WW2, then the value of achieving that military objective exceeds the value of the 1000 civilian lives lost, because by ending WW2 may be millions of lives, billions in infrastructure etc., can be saved. Using the example of the Jabalia refugee camp bombing that took down a Hamas commander, it did not meet the requirement for proportionality, as even after that bombing, Hamas is still firing rockets at Israel, so clearly that commander did not matter, so no significant military objective was met or advantage gained, for the many people killed there. Hence, war crime.
Israel fails in almost all of these cases, barring except may be a few, as their reasons for dropping bombs and attacking civilian locations are often times flimsy and instead driven by pure racial hatred and religious zeal disguised as "self-defense" which is quite evident in the rhetoric used by Israeli politicians. Quite simply, they are committing war crimes and I won't be surprised if the ICC investigation finds that to be the case.
Here are some links and excerpts I found:
The principle of proportionality prohibits attacks against military objectives which are “expected to cause incidental loss of civilian life, injury to civilians, damage to civilian objects, or a combination thereof, which would be excessive in relation to the concrete and direct military advantage anticipated”.
4. Indiscriminate attacks are prohibited.
5. Among others, the following types of attacks are to be considered as indiscriminate:
(a) an attack by bombardment by any methods or means which treats as a single military objective a number of clearly separated and distinct military objectives located in a city, town, village or other area containing a similar concentration of civilians or civilian objects; and - Israel does this.
(b) an attack which may be expected to cause incidental loss of civilian life, injury to civilians, damage to civilian objects, or a combination thereof, which would be excessive in relation to the concrete and direct military advantage anticipated. - Israel does this.
6. Attacks against the civilian population or civilians by way of reprisals are prohibited. - This happens in the West Bank, and infact is happening now. I also suspects it happens in Gaza, because of the rhetoric used by Israeli politicians.
7. The presence or movements of the civilian population or individual civilians shall not be used to render certain points or areas immune from military operations, in particular in attempts to shield military objectives from attacks or to shield, favour or impede military operations. The Parties to the conflict shall not direct the movement of the civilian population or individual civilians in order to attempt to shield military objectives from attacks or to shield military operations. - Hamas possibly does this.
8. Any violation of these prohibitions shall not release the Parties to the conflict from their legal obligations with respect to the civilian population and civilians, including the obligation to take the precautionary measures provided for in Article 57 . -
casebook.icrc.org