Is drunkenness necessarily a sin?

Is drunkenness necessarily a sin, like hating God, or is it just because God decreed it to be? This is of particular interest to me because Rabbinic Judaism claims that it is not (It's only allowed on Purim) hence one could argue the following: 1. Rabbinic Judaism says that getting drunk is not (always) a sin. 2. But getting drunk is always a sin. 3. :. Rabbinic Judaism is false. Is this a sound argument? I know Aquinas and the Catholic Church would say yes, but advocates of some versions of divine command theory might say no. But it's also true that getting intoxicated can be allowed in a medical context although presumably in that case you're in a sort of controlled environment and there's a proportionate risk of bodily harm. Also Judaism concedes that sins committed due to getting drunk on Purim are still sins hence doing so may be a sin for some people. **Note:** Just for clarification, especially for those who don't speak English natively, we're talking about getting severely intoxicated, not just drinking alcohol.