Isn't there a grey area with this, seeing as civilians are indeed being handed weapons and being brought in to the fight alongside military? In this specific case surely it makes the cause:effect relationship a bit blurry?
I think it is more a case of once a free corridor has been setup and civilians allowed to leave, any left are not counted as civilians, they should have left when able, so once the heavy bombardment starts, no one should shout, what about innocent civilians in the area.
Well they had their chance, they didn't leave, so tough, there are no innnocent civilians left, Russia will say.
It has been the same rhetoric in previous battles in Syria, and Georgia etc. So I don't see it being different here.
And yes to an extent the arming of civilians has already meant, Russian attacks on residential areas can easily be countered by, well they shot at us first, we only shot back.
The reports will not say that of course, they will only show Russian shells and missiles hitting residential buildings, with zero context, such as an earlier gun battle from the building towards Russian soldiers on the steeet, who then just radio in for artillery support, as any army from any country would do.