"Art is not money, best portraits are art, not what you're striving at." Phototron
There is no contradiction at all between professional and art photography. The best is saleable;the worst isn't; irrespective of how you classify it. The worst may not be saleable perhaps because the photographer is the ONLY one who thinks it is art and the ONLY one who would want to look at it more than once.
The role of the serious portrait photographer: professional or artistic is to flatter the subject, create the best possible shot of that person reflecting possibly beauty, style, character, charisma, mystery, personality etc.
The photographer through technique and composition has control of the shot, so that in evaluating the artistic/commercial quality of the work the following question is basic:
Does a particular picture element contribute to the overall effectiveness of the photo? If it does then you emphasize it. If it doesn't, then you de-emphasize it, so that it does not detract from the photo.
Josuf Karsh did a portrait of Churchill. What he wanted to portray was the power and charisma of the man which he got through the facial expression. He certainly did not want to distract viewers with an image of a short, fat, politician, whether "real" or not. He de-emphasized Churchill's girth using dark colours and lighting.
You may think that freckles are pretty, but unless you are a woman and has them, then I take your view with a large grain of salt. I am sure there are those who rationalize wrinkles as character lines too, but most would certainly prefer not to have them and considering the growith in cosmetic surgery, many are rushing to get rid of them.
Bottom line of most portrait subjects which I happen to agree with, is that they realize that their face or body is not perfect but want people to see past that..to the real person inside. The role of a serious portrait photographer is to help the subject achieve that goal in a high quality commercial/artistic portrait. It can't be done by distracting viewers with skin blemishes, minor teeth problems, zits, moles, scars, or even freckles.
To repeat again, these distractions are NOT eliminated, but they are de-emphasized by a good photographer so that the viewer can see "past them" to the "real" person.
skieur