They're decided by weirdo religious people with too much time on their hands. Similar to, I'm pretty sure, the people who decided that any beverage over a certain abv (alcohol by volume or, as my best friend and I like to call it "octane rating") is relegated to a state-owned liquor store, with limited operating hours.

I'm fairly certain any beer over 4.5% (or is it 5%?) abv is classified as "malt liquor" and subject to some really stringent laws in Utah.

Just as a reference, Corona Extra and MGD are 4.5%, while standard Budweiser is 5%. It's conceivable that Anhei$er Bu$ch would make a special Utah recipe.