This is literally what she did though! Why else would you not just erase but rewrite with random data? In fact, why were they deleted at all?
Sure, he paraphrased it for the layman. They don't understand what rewriting with random data means. A good analogy is "bleach" which is also the name of the program.
Yes, he dropped in "chemical" in there unnecessarily, but this doesn't make the overall point invalid.
I do essentially this on a regular basis. It's SOP when I'm done with a piece of electronics. It has nothing whatsoever to do with the FBI -- it's because I don't want anyone who finds (or buys post-consumer) the device to find my data on it.
I'm currently procrastinating on recycling a couple of old busted Android devices specifically because it's a real PITA to scrub them with any degree of confidence when they're busted.
So yeah, if you look up how to clean a disk, you'll probably find an answer like this. An analogue is even baked into the ATA spec: "security erase enhanced". But actually doing a "security erase enhanced" is bizarrely tedious, especially on Windows, so overwriting it is.