People can and do argue about the morality of the Tokyo firebombings and Dresden and Hiroshima and Nagasaki where it was largely purely civilian populations in cities that were attacked, but I think it's _fairly_ non-controversial that in a total war that industrial sites and weapons manufacturing facilities and so on are valid targets in a war situation, and they are generally staffed by non-combatants.

The rule in the geneva conventions is: "In so far as objects are concerned, military objectives are limited to those objects which by their nature, location, purpose or use make an effective contribution to military action and whose total or partial destruction, capture or neutralization, in the circumstances ruling at the time, offers a definite military advantage."

Which encompasses quite a large category of non-combatants that are likely to be in the area of those "objects".

edit: not making any kind of judgement or statement at all about this particular situation -- just clarifying in general the rules of war involving non-combatants.