First of all, depression is characterized by people who have distorted thinking about themselves and rationalizations for avoiding treatment. So that discussion is going to be necessary to have.
Secondly, it's reasonable to be skeptical about psychiatry and self-help books. The industry is saturated with snake oil. One has to rely on one's own judgment or one would be endlessly drowning in research. Judging books by their cover isn't just appropriate, it's mandatory.
Sometimes literally. One of the best-selling self-help books for CBT depicts a guy with a lobotomized smile floating in a dreamy cloudscape with the title "Feeling Good".[1] When it was prescribed to me I was disgusted. It looks like Stuart Smalley.[2]
But people who made the same mistake were corrected by others who had read research, or had personal knowledge. Which leads me to my last point: head-butting has its place. In the wild, animals who butt heads are doing so to determine which is the stronger, without actually engaging in wasteful combat. Similarly we are often arguing to probe which argument might be better, without fully testing it. It's enough, sometimes, to sense someone's confidence, to see a glimpse of the detail of their knowledge, even if they don't cite anything.
That heuristic is highly exploitable by people who have abnormal abilities to project confidence (aka, "confidence men"). But it's all we've got in a world that none of us have time to fully investigate.
At the very least, in that discussion, I hope people learned they couldn't just dismiss CBT out of hand; intelligent and experienced people had decent arguments for it.
[1] http://www.amazon.com/Feeling-Good-Handbook-David-Burns/dp/0... [2] http://schlegelrock.com/wp-content/uploads/2011/03/stuart-sm...