It's not that they advertised normal hangers and sent small hangers. Technically, they advertised small hangers. You can't tell that from the photos (no size reference) so most people just assume that they're selling big hangers. They design the listing as misleadingly as possible, so that you have to read very very carefully to catch it.
If they just shipped a brick then they've committed fraud. If they ship a product that's technically exactly as described, then in a sense it's the buyer's "fault" for not being more careful about what they were buying. Many buyers will even blame themselves once they realize and not issue a dispute.
It's probably still fraud. If it seems dishonest to the average person, it will probably seem dishonest to the average judge. The law is more sensible than most people think.
I'm not a lawyer. I've just sued a few people.
Nothing was hidden! There was no deceit! If I say I’ll take your money if you let me, and you let me, you were not defrauded. You may have been taken advantage of. But it’s not fraud. (Also, they now have your money. To pay lawyers with.)
Did you look at the photo in the article? You can easily tell that they're tiny hangers. If those were normally-sized hangers, the hooks would be something like 5 inches in diameter.
The trick doesn't have to hold up in court. It doesn't even have to hold up in the website's fake court. It just needs to convince the victim not to bother fighting.