I vaguely remember sama had a comment some time ago, kind of related to what you are saying here (paraphrasing here): "being contrarian is easy, being contrarian and right is hard." Working on a seemingly bad idea is being contrarian by definition, that's the easy part. And if people just take the advice at its face value and intentionally work on "bad ideas", that's being a fool. The real hard part is "being right", which requires the founder to have a unique vision or belief in his idea, and drives it really hard, maybe even to the point of being "delusional" to outsiders, but again, being delusional about your own idea doesn't guarantee it's "right".
