As a hyper-miler who aggressively monitored fuel consumption, I am absolutely, 100% sure I got better fuel efficiency with the windows down except at the highest speeds with my Honda Fit. As in, an ~8-10% increase with the windows down and AC off during off-highway driving. My car was rated at 32mpg, and averaged 44-45ish without the AC, and 40-41 ish with it, in warm weather, on my current commute. A few years ago, when my commute involved a lot more stoplights, it was more like 38-39, vs 42-43mpg.
I havent driven the 5th gen much (it is the wife's), and understand the AC uses a much smaller portion of the larger engine's power, but my initial observations show about a 1-1.5mpg decrease with the AC on vs windows down/AC off during my current, relatively-fluid, but off-highway commute (21-22 vs 22-23mpg, on 33" tires).
I understand the mechanics of the fuel consumption differences between the aerodynamic drag of windows vs the AC, and understand in certain circumstances like constant higher speeds the AC is more efficient. But, calling it universally "myth busted" is an absolute overreach

. Hell, even in that episode their findings matched my own regarding windows down being more efficient at lower speeds.
Of course, there is a certain dollar value for not showing up to your destination sweaty, but when im just bebopping around in a T-shirt on a nice day, Ill take natural cooling every time!