So we're supposed to just wait until he's emergency-killing those civilians to avoid discovery/steal from them while on the ground, like the Russian bloke did? Or bombing cities, killing hudreds or thousands?
We're not going to get rid of the convention just because some people commit war crimes, like killing civilians. That's what the convention is for, or else it wouldn't be a war crime.
By your logic, the russian dude just killed all those civilians because they would eventually become Ukranian combattants who would kill thousands. He still shouldn't be killing those civilians, like we shouldn't be killing parachuting pilots or medics. It's pretty simple