There's a huge difference between saying "tormenting these scammers, vigilante-style is unsettling and perhaps distasteful" (the takeaway I got from the This American Life story) and saying "Nigerian scammers are good people".
They can be bad people, some of their number may have murdered people, but I don't think that makes any and all actions toward them justified.
http://www.thisamericanlife.org/radio-archives/episode/363/e...