I would go as far to say that using a hospital or civilian building as a base of operations to launch missiles from is the war crime in this scenario. If innocent people die from retaliation for that, the blood is on the hands of the people who chose to use civilians as meat shields and make them a target in the first place.
Edit: To be clear this isn’t a pro-Israel comment. Fuck them. I was just saying that if Hamas actually used hospitals as launch sites or military bases they would be the ones who are responsible. I don’t know for certain if they did or didn’t at this time.