Marketing, like IT, is infested with people who think they know what they're doing, but really really don't. In both fields, this devalues actual professionals.
I trained in IT (Comp.Sci. degree), and my lovely & talented wife is a marketing & PR professional. I noticed a while ago that our complaints were symmetrical: people tended to undervalue what we did, and indeed the entire field. There was also a tendency for people to jump in and try to do it for themselves, with consequences that were usually either hilarious or tragic depending on how close the observer was to the results.
Now that I am receiving formal training in marketing, I am getting it from both sides. At least I am prepared!