I have a PhD in chemistry, so I've been through all the classes mentioned.
Organic is, in fact, the only one you absolutely CAN memorize. Unlike the math-based chemistry classes where you have to learn principles, which the pre-meds struggle mightily with, the memorization-heavy organic chemistry is the one that is considered to be similar enough to medical school that it is used as a weed-out.
This is particularly true of organic *synthesis*, vs. organic *mechanisms*. Mechanistic organic is often presented as a first semester organic class, and that does actually require knowledge and understanding. Synthesis, however, is nearly straight memorization, even if you don't want to.
I was happy when the pre-meds stopped taking the major-level chemistry classes (mostly after organic). It made my physical chemistry classes much more interesting. It didn't keep the one pre-med in the class from whining the entire time that he wasn't getting the answers spoon-fed to him from the book, though.
So I don't know where the author is coming from, because they completely got it wrong.