Where did the sudden insult "edgy" come from?

Back when we were kids, if this Pokemon was around, we would have thought it was badass looking. Personally, I still think it does. But now, it seems that, if something has sharp edges or a dark concept, it's considered "2edgy4u" sarcastically. I've seen most of the hate like this directed towards this guy, Darkrai, etc. Why? Why can't anything look badass instead of "W0w such edge"?