It would seem to me that you are effectively treating society as this single entity and saying that so long as an action benefits that entity then it is moral even if the action itself would be considered immoral in another scenario.

However society is not a single entity, but rather a collection of individuals that can be affected by an event in different and often opposing ways. To some it may be beneficial, but to others not so. Sure the group that benefits may be in the majority, but to ignore the minority group and declare that to "society" the outcome was good is to ignore the different views and interests that make up a society.