Isn't that a market law? Buy low, sell high. Where you found the products or what you do with them is not relevant. (as long as you're in the legality, of course)
I feel your disgust for such people who also feel like the smartest on Earth, but setting up a website or using a sell/buy app for "dropshipping" still requires some efforts to create and maintain. It's not like they get dropshipping for free, even though it's not a big effort it still requires some.
Searching through those websites for products is actually very time consuming and most people don't have the patience or will to sit for hours hunting cheap products. They just want a quick way to buy nice products at a good price. Even if the original price was much lower and the dropshippers are earning a lot, for the final consumer that's still a good price and they saved up a lot of time searching around.
It was a nice article anyways, it sparked many thoughts :)