Of course you are correct that targeting civilians with weapons of any kind is illegal, but even foreseeable but unintended civilian deaths are not war crimes. In the days before smart bombs, wars could not be waged without such a loophole. That is why we have the concept of collateral damage, where the intent of the targeter determines whether a crime has been committed, not the effect of the action.
Were you aiming at that military base in the middle of the city (or at those weapons storage bunkers surrounding the mosque in the suburbs)?..or were you purposely targeting those civilians?
And even if a city doesn’t have a military base in or near it, it probably has several defense industry facilities, and if not that, perhaps some power generation facilities which power defense industry facilities elsewhere. It’s this gray area which allows people some weasel room.
