The legal question is whether the civilian casualties are proportional to the concrete military value of the target.
A question that's worth considering is whether, when considering proportionality, all civilians (as defined by law) are made equal in a moral sense.
For example, the category "civilian" includes munitions workers or those otherwise offering support to combatants on the one hand, and young children on the other. It also includes members of the civil population who are actually involved in hostilities without being a formal part of an armed force.
The law of armed conflict doesn't distinguish these; albeit that I think people might well distinguish, on a moral level, between casualties amongst young children, munitions workers, and informal combatants.