Granted, I'm really lucky to live in PDX because we have such good access to great coffee it's made more noticeable. In my youth, I was actually of the same mindset until drinking a lot of different coffee and discovering my "misguided" way ;-)
Note that the initial time of small decrease of pH corresponds to under-roasted coffee, and coffee with this degree of roast would be unacceptable even to fans of light roasts.
That's more about the low grade beans, robusta beans and a very dark roast. Dark roasts are much harder to identify as "stale" because they have basically only got a burnt flavour. As a general comment (not directed at parent) if you get the chance to buy some green beans, have a go at roasting them and taste the difference between different roasts. You don't need anything flash to roast them, I use a heat gun. It's cheap, easy and the coffee is never stale.
I personally like roasting in small batches, because I don't drink a _ton_ of coffee, and it only takes a few days for roasted beans to lose a lot of their volatile flavor compounds.
Not going to make a claim I can't back up, but a lot of people take acidity to equal flavor - which is why Starbucks coffees are insanely acidic. Whether or not that's why the author prefers iced, hot-brewed coffee (for the acidity) and is conflating that with flavor, is not something I know for sure, but it's a possibility.