I also found an article about virtual sex role play in which adults use child characters:http://www.theregister.co.uk/2007/11/01/sickos_in_sadville/
So these are the points I've noticed were being made by the articles:
- CG or animated child porn, while mostly harmless in manufacture, may encourage pedophile urges and subsequently cause more abuse in real life. They admit that there has been no real connection found however between abuse rate and cartoon porn just as there has been no connection found between violence on TV and real life aggressiveness.
- Cartoon porn and video game porn, even while accessible only on adult websites, may still be used (downloaded presumably) to groom children for real abuse. Again, there is no proven connection.
- Cartoon porn is repulsive in the authorities' opinion, and socially unacceptable.
I personally had a crush on Lisa Simpson growing up. On occasion I've found some Lisa Simpson erotica that isn't total crap like most are, and I've readily used it to get off on. I've also done extensive online sexual role play, though not in Second Life, and unfortunately I took it way overboard.
Whether cartoon porn leads to child abuse (and I doubt it does), I believe all porn is nearly equal unless force or coercion was used in it's creation.