I laugh at bad cosplay, too. But I kind of don't do it in a "Haha! I could do better!" way, since I don't cosplay anyways and think it's all dorky and nerdy (but in a delightful way :D). To me, a bad cosplayer is just about on the same level as a cosplayer that takes 3 years building the perfect costume and spends all of their parents' money on a Con. Rofl.