> Are you advancing the argument that abuse of children is an economic response to demand, and not that the perpetrator wanted to do it in the first place?

There is abuse of children, then there's the act of making recordings of it for others to consume. The latter certainly functions on a demand curve, as it takes more work to produce something than it is to just do it.

> How does this argument explain the illegality of drawings depicting underage sex with none of the depictions being based on a real-life individual?

There probably isn't much rationality to it. Legislation is more of a political process than a rational one.

> I believe that it's more consistent to believe that society finds paedophilia to be disgusting and that due to their disgust that paedophiles should be jailed.

I would agree with that assessment. But there's also a shocking amount of truly, unbearably horrific content in the world. Disgust may not be the most rational basis to make something illegal on, but it's better than nothing. Laws are intended to be iterated on over time, a more nuanced view will eventually prevail, though it might take decades.

> It's a somewhat risky viewpoint to espouse that "paedophilia in and of itself should not be illegal, abuse of a victim should" given the fervor of the people against paedophilia, but I think it is more congruent with a living in a free society.

Paedophilia is not illegal. It's child abuse and possession of child pornography that's illegal. You can't convict someone of being a paedophile, there's no law against it.