Funny, when I dowload MP3s I also have to tolerate kidporn... what a strange idea. I guess someone is afraid of loosing his kidporn source. Downloading MP3 is legal in my country or philosphy (ist still buy CDs to support my favourite artists), but I won't support sexual abuse of children.
However I still wonder if trading kidporn is happening inside Gnutell or only a very little vanishing fraction.