Problem is that applies to almost any given subject. People do no say "I am not a chemist" even though I can probably find an exception to almost any stamtent about chemisty made by someone without a degree.
Try listening to secondary (high) school Chemistry teachers... they have degrees and still teach complete rubbish most of the time. I can understand teaching things slightly simplified, but teaching something which is actually outright wrong in the name of simplicity is just crazy.