Few points:
First, your general point -- "dogmatism is bad" -- seems easy to grant. To that I would only add, "Mean people suck."
Second, people who have learned to listen may have more to say than people who haven't, regardless of age. I used to think that if I was having a problem with my computer, I could just ask any nearby teenager or twenty-something. Turns out, most of them don't know how these things work, either. Find someone who knows, and age is irrelevant. Indeed, people using computers longer know more because you had to do more to get them to work, early on.
Third, if my hearing is that of a 50-something, why wouldn't I want the advice of someone in my generation, with a roughly commensurate hearing ability? We don't ask kids about the taste of wine because their taste buds are not in the same state as ours, and their preferences are wildly different.