I don't think that was the point of the article. I read it rather as pointing out that posing as a founder when actually just buying equity is not ok. The key difference is personal engagement ('I asked two questions. The first was “is he going to be full time with the company” and the other was “do you want him as a third full time partner.” The answer was no and no.'.)
If I told a YC-caliber startup that I'd give them $18k for 6% but wouldn't be able to make any introductions, then they'd probably tell me to take a flying leap. So, effectively, some part of a YC-like incubator's equity take is compensation for introductions.