Earlier quoted context omitted.
Well, you can weigh the apple yourself on the scales that occur all throughout the produce section... but yeah, I'd be surprised to see a flat rate for fruit by species no matter the size. Fruit is sold by weight, not count, in China too.
That wasn't their point. In most of the world if a product's price tag says X then you pay exactly X at the register (e.g. £2 sandwich costs exactly £2 in cash, you hand then exactly £2 and leave). In the US that is not the case. Almost everything has a "hidden fee." You go buy a $2 sandwich but pay $2 + 6% ($2.12), if you get food in a restaurant you pay $price + 15-20%, an advertised $30/month cell phone plan is ac…
In some states, there is sales tax. In others, none. Sales tax may or may not be applied to clothing depending on state. Sales tax may or may not be applied to food, or only some kinds of food (e.g., alcohol always taxed), or only to food above a certain threshold.
All in all there's nothing hidden about sales tax. It shouldn't be a surprise that people are expected to know how the sales tax system in their state works when they are interacting with it every day.