Commandments and consequences can change over time. The scriptures provide examples of this, including with laws of health. There have been times when having a little wine was not a sin. Today it is. And at the second coming if I am served wine and commanded to drink it, I'll do it (See Matt 26:29, D&C 27:5). But until the commandment changes, I'll continue to say no thank you.

It should be no surprise that new commandments can be given. In fact, if you keep the commandments one of the blessings you'll receive is more commandments. See D&C 59:1-4 which talks about the blessing of "commandments not a few". It works generally (e.g. the saints are now commanded no alcohol although it used to be different), and it can also work individually (Elder Bednar once taught this principle in a local meeting and he gave an example of something he felt he shouldn't do even before he was a general authority, but he said the general church population and even his wife are not under the same restriction).

You interpret it your way, I'll do it mine.

and

When prophets contradict each other and scripture, it's usually safe to rely on what Christ said as a back up plan.

Scripture is not for private interpretation, but requires the Holy Ghost (2 Peter 1:20-21). It's not "safe" unless you subscribe to the "all roads lead to heaven" philosophy, because people will surely interpret things differently. You need prophets, other scripture, obedience, and the Holy Ghost to correctly interpret scripture.

But whatever the reasons a BYU fan is drinking (non-member, member lacking a correct understanding, member who'd like to quit but is addicted, etc.), I also say welcome! I'd rather see a smoker in a BYU shirt than someone in a BYU shirt being rude to others.