I don't remember that article but to answer why a lot of people teach that hang start position first is simply that it's important. You can teach a bunch of other things first, but why distract from the most fundamental?
Regarding how long it takes to learn the snatch, I've taught some people to do pretty impressive snatches in a few minutes; others take months before they demonstrate something really sound. It depends primarily on the characteristics of the athlete and less on the way they learn in my opinion. A very talented athlete will end up doing it well even with the worst teacher; a very unathletic individual will struggle even with the best teacher.