The anti-imitation viewpoint (what I call related to the "Art" perspective) is wrapped up in two ideas: 1) that people should be "individuals" in their drawing style — different from other people. 2) That drawing is an imitation of life (Iconicity), and that a person's style is simply their own manner of siphoning those visuals into graphic form.
Both of these run against the "Language" perspective which pushes communal signs that are conventionally shared amongst a culture, learned through imitation. In Language, it isn't so much a matter of using novel structures (words, drawing styles) but of using those structures to say something interesting and novel.
What I thought was interesting about this post in particular is well expressed in this paragraph (italics from the original):
Don't imitate John Cassaday, find out who John's inspirations were, whose work he learned from, and imitate them. Because even if you can imitate John's work, or Jim's, or Frank's, etc., the best you can achieve through imitation is a mimicry of style, and to be known as an imitator. Style, good or bad, is really the only thing that's going to separate you from the pack, and it's not something you can add into your work. Not really. Style is where your personality surfaces in your work, and true style is accidental.
The underlying "Art" sentiments should be obvious here, but what's interesting is the belief that it's okay to copy somewhat, just not of the "generation" right before yours. It didn't just say "don't copy other people," instead it argued for people to copy the artists who the-artists-you-like copied!
While I understand the argument, and can sympathize at least somewhat with the sentiment in terms of creative endeavors (i.e. the type expressed in the Dylan quote at that articles start), what really makes copying one generation's drawing styles different than any other? Why is there this assumption that there is a degradation that occurs from one generation to the next, and that somehow there is a more "pure" root that aught to be copied from?
If anything, this lesson in history should show that everyone is influenced by other people and that you can probably trace those influences so far you'll lose track of who the actual people were. So, why not embrace the imitative styles since its what we're mentally inclined to do in the first place?
I love the Language equivalent of this: "Don't learn to speak English from your parents and peers! You should learn from Middle English... Those guys really knew how to speak back then!"