I would have to strongly disagree with your professor. While there are many artists who paint but are not able to articulate why they paint a certain way or paint a specific subject I think it may be demeaning to assume that every (or any) artist queried could not explain why their work may be perceived as "good" or "bad" or under what context it should or would be considered "good" or "bad".

A question: Do you think it's treading on dangerous ground to allow a few individuals (art critics) to dictate to the public at large what they should view as good work and how they should determine this? Does that not subjugate the viewing public's personal perceptions if not completely dismiss their value?

He meant artists looking at the work of other artists.

Critics have determined public perception of art for a long time. I think this can be dangerous. It isn't unusual. Haven't the educated elite determined public perception of many matters? I think people lack education in art, don't trust their own response, so as you said, a critics words often carry more weight than individual experience. People tend to cede their response to the authority, not questioning the validiity of the authority.

If people don't have or don't take the opportunity to find out for themselves, to stand before a painting or whatever, then could could be misled into believing a critics word is gospel. As an example, the prevailing attitude toward Jackson Pollack is that he was a lucky hack. I more or less went along with that until I saw one of his paintings in person. I was in awe. That experience led me do look more closely not only at his work but others of that period and learn the ideas and motivations. If anyone is interested in learning more about a particular artist, movement, and so on, opportunities exist outside of gallery visits.