Does anyone remember Color Labs? Go read this thread and marvel at the similarities: https://news.ycombinator.com/item?id=2364463. A stellar team backed by top VCs who invested (extraordinary at the time) $41M sets out to build a location enabled photo-sharing app. VCs tout it as "the next Google". Most of HN is pretty critical with some voices advocating caution and saying "let's not be so dismissive, maybe there is something more to it". Well, it turned out there was nothing more to it.
So no, being dismissed by HN does not automatically mean that your idea is good and you will be successful.