Agreed. Parent commentor is statistically wrong. A large number of SO answers are helpful but he found an anecdote to wrongfully preach generalization. Also, OP's question violates SO guideline in the sense that answer to this question would be highly opinionated.
Yes, I'm not saying that Stack Overflow doesn't have "birdies". For example, I really enjoy this user's consistently high quality answers: https://stackoverflow.com/users/224132/peter-cordes
This is tangential to the meat of your comment but I feel compelled to nitpick based entirely on personal anecdote: I have been helped hundreds of times on StackOverflow by people who had nothing to gain from it and yet provided in depth, insightful answers. In my experience, the farther you get away from the big, overwhelmed tags, the better the quality is. But you don't want to get so obscure that you are just ignored.
The Racket community on SO is particularly fantastic, and (in my experience) the more 'web' related your question is, the worse answers you get.