Honestly, Tipsy. I mean, in all sincerity, I believe you don't understand the concept of manners. If the fact that "it isn't an issue for everyone" makes it acceptable, you've just ratcheted "manners" down to the least common denominator, and passing gas at the table is mannerly, because it "isn't an issue for everyone."
Since you asked me to justify this simple polite convention I will. A wedding reception is, for many brides, grooms and their families, a once in a lifetime affair. They plan carefully and provide as generously as they can. They see it as a point of pride to provide for their guests and, to the extent that they can, to make it a "perfect" affair. That's the stage onto which the OP walks. He finds that there is no beer to his liking. If he is polite, he chooses to either drink the beer offered or to do without and drink something else. He does this because he respects his host and hostess, and he is willing to forego his desire for a "good enough" beer so that the host and hostess have no reason to believe that they've not provided well enough for their guests. He does this because he knows that to do otherwise is to say in unmistakable terms "Yes, you tried your best, but you failed. You failed to provide for me. I want better than you have offered." He does this because he knows that to do otherwise is to be an ingrate, and a boor. Manners and courtesy VERY OFTEN mean that not everybody gets exactly what he wants when he wants it, seeing the importance of putting someone else's feelings before his own.
I don't own this simple and, in many circles, well-known and respected convention of what it means to be a good guest. I won't defend it further. Please let it be sufficient to say that I acknowledge its existence while you, for whatever reason, deny it, and let the conclusions be drawn as they may be.