What is wrong with watching child pornography? Let's be clear that child abuse is wrong, and anything that makes more of it likely in the future is also wrong. Even if we agree that watching child pornography which encourages further harm to children is wrong, it seems less clear where the wrong is in doing so when there is no chance of causing harm. There are many pictures of adults and children who have been harmed to an extent at least on a par with the victims of such child abuse from the current wars in Iraq and Afghanistan, and we do not normally think that viewing those images is wrong or makes us complicit.
The most obvious candidate is the motive of sexual gratification on the part of the viewer. What makes that different from the motives of readers of bombs in the Middle-East? Is it the fact that the viewer must have a deviant sexual orientation or because they are benefiting from the harm in a way that the reader isn't? The first reason seems off the mark since it seems that the act of viewing is wrong and the sexual orientation it reveals. The second looks more plausible, but a reader might have a strong preference for articles about bombs, and benefit inasmuch as they satisfy their preference.
In most domains in our society, the prevailing idea is that censorship is wrong unless it directly harms others. Usually, we say that media - text, images and videos - are free to consume (in the sense of legal freedom, not cost) and the traditional liberal reason seems to be that however appalling we may find the content of such media, it simply contains more information about the world. Various exceptions have been raised, like inciting racist violence, but there's a clear harm consequence which doesn't feature here. Also, if we wanted to ban material that harmed people by exposing their suffering to others (even though they're not aware of their exposure) then photos of bomb victims should not be acceptable.
I'm being tendentious on purpose because there's very little critical discussion of this topic, even in broadsheets. It seems to be that if the suffering and long-term trauma of children is what makes it so bad then we should be clear about that and focus our anger on that. Is there anything to be gained from demonizing people for merely looking at something that almost all of us agree is wrong?