I’m beating a dead horse, but if you don’t want to allow caffeinated soda on campus, just say so. Say “it isn’t in line with the culture we are trying to cultivate”, or “we feel it is unhealthy for the students”, or heck, even “we believe it is against the Word of Wisdom”. But “there’s no demand” is a bold-faced lie. As in, Orwell’s 1984 quality of lie.
If I can’t trust you to be honest on the simple things, how am I supposed to trust you on the difficult things?