The study cited states clearly that the tax is for sugar-sweetened (including HFCS) beverages only. The full quote related to "diet" beverages actually is:
"A controversial issue is whether to tax beverages that are sweetened with noncaloric sweeteners. No adverse health effects of noncaloric
sweeteners have been consistently demonstrated, but there are concerns that diet beverages may increase calorie consumption by justifying
consumption of other caloric foods or by promoting a preference for sweet tastes.34 At present, we do not propose taxing beverages with
noncaloric sweeteners, but we recommend close tracking of studies to determine whether taxing might be justified in the future."
This would also preclude 100% fruit juice drinks - although "juice" - the mostly sugar and water kind - has been touted as a victim on commercials against the sugar-sweetened beverages tax, which is
disingenuous, at best.
Last time I drank a Fresca, it didn't have sugar in it - nothing to worry about for the article writer. Granted, there's no ends to what governments will put a tax on, but to derive an article
that may have no purpose other than to upset and anger persons from a one paragraph that doesn't exactly say what you say it does is somewhat
irresponsible.