It is definitely terrible advice. It sets people up for a long investing career full of behavioral errors and vain attempts to beat legions of people and machines better than you at actively trading.
No, it just gets them started. There is no mention in the piece about this being the way to invest for the long-term, so no one is getting "set" on anything. It doesn't suggest you can "beat the market" or appeal to anyone's vanity.
I believe you are underestimating the perceived complexity in investing by people who don't understand it at all. I also believe you are underestimating the amount of diversification that a dozen stocks chosen from different industries can provide. It's better to start sub-optimally than not start at all.
