Can an Army event be mandatory inspite of alcohol being served?

My unit (regular, active army) is forcing attendance to an event after normal duty hours and at which alcohol will be served. I understood at one time that no event can be mandatory if alcohol is being served, and I would like to be excluded from the event because I dislike being around drunk people. I also desperately need a regulation reference to help combat this problem. Any help is appreciated because I just get the "suck it up and drive on soldier" answer from my NCO support channel and chain of command and I would really like to avoid the vindictive issues that arise from going to the Inspector General. Thanks.