Historically, society has drawn a line between "art" and reality - even when it comes to porn. And, with a few notable exceptions that seem to always draw objections, society has said that thoughts are not crimes.
Kiddie porn that involves real kiddies is, we all seem to agree, bad. (Well, the non-NAMBLA folks do, at least.) And I believe that we can stipulate that there is a fairly well established nexus between "make-believe" kiddie porn and real kiddie porn. There is, based on the literature, not such a nexus between kiddie porn and child sexual abuse as we generally understand that term/crime - sexual acts with a child by someone in a caretaker role, as opposed to the sort of child rape prevalent in kiddie porn. So it seems the debate here is whether we should be locking up folks who read kiddie-porn literature or view kiddie porn comics/cartoons on the basis that they might graduate from make-believe fictional representations of kiddie porn to real live kiddie porn with real live kiddies.
Thought crime before the thought is even formed. They "might" do it. It's for the children!
On the same basis I guess we ought to arrest everybody who possesses a ___ because they might use it to hurt/kill someone else. Or a little less out there - we ought to arrest all Little League coaches because they might molest a kid on the team. Do not get me started about arresting priests to prevent the possibility of them doing something doubly (triplely ?) horrific with altar boys. And all teachers, day care providers, and boyfriends of the kid's mother must go, too.
On the othrer hand, I do view those that "merely" purchase porn involving real kiddies to be accessories to crime in the same way that johns are accessories to the crime of prostitution and drug addicts are accessories to the crime of drug dealing.
I have about 16 years of experience working with both caretaker-role sexual abusers and folks who acted in kiddie porn. While occassionally there is crossover (making a home movie of yourself with the 3-month old), my experience and training is that 1) the crossover when it involves sharing/selling the product is rare, and 2) most of those involved did not graduate from viewing/reading artistic (fictional) representations to commiting physical acts. As a matter of fact, those deeply into the viewing/reading of fictional representations found the mere thought of actual physical sexual contact repugnant - through fiction they could keep it clean and "pure", not messy and smelly and icky. Also, in the fictional representation the "partner" not only was willing but enjoyed it, as opposed to the expressed fear that the child might cry or bleed or, worst of all, vomit.
Folks involved in sex with children, be it imaginary or real, are very sick persons. But their sicknesses generally are different based on imagining as opposed to actually doing.
stay safe.