The problem with anecdotes is that they often lead to faulty conclusions. Saying they are better than no evidence flies in the face of the (anecdotal) evidence of the people who say monks are OP, or psions or OP, or wizards aren't OP, or ToB is broken, etc.
Anecdotal evidence is evidence, sure, but not necessarily better than no evidence. You could say anecdotal evidence has a tendency to be...
contaminated.