Russia is directly, intentionlly killing the civilians in question in Ukraine. They're doing it on purpose, aiming for the civilians, to terrorize them into submission (and Russia has a very long history of this form of intentional terror-war against civilian populations in the name of conquest). Russia's genocide of Ukrainian civilians isn't a mistake of aiming, it's not an accident of war, it's not a whoops, they're trying to kill them and starve them (see what they're doing to Mariupol at present).
The difference between the two situations is exceptionally obvious and morally clear.