I agree, it is a fine line. Another relevant inconvenient truth is that there are pedophiles who have never acted on their urges, never harmed a child, and have even sought appropriate therapy to manage their mental state. Yet at the end of the day, they are still literally pedophiles.
Japan seems to be the canary in the coal mine for this issue. They have long made it legal to draw manga "pornography" featuring apparently underage characters, as long as it doesn't depict an actual child in any way. This is a vice mini-doc on the subject from a few years ago.
People in that culture try to make the argument that it gives pedophiles a way to manage their feelings without harming any children. But in reality, it's seeming more like giving suicidal patients access to guns. The challenge seems to be that: philosophically we want universal free speech, but biologically the human brain isn't evolved to control itself in that environment. You're not staving off a pedophiles' urges, you end up nurturing them. You create a subculture that embraces this mental state as acceptable and normalized. It would be like....building Westworld robots for serial killers to abuse. Surely nothing good will come from creating a safe space in society for people with these urges.
I personally do not agree with any laws against speech, and also I don't think anyone should ever create "artificial" CSAM in any capacity. But I don't know how to square that circle. Because if you try to just make a blanket law against it, on the one hand people will find ways to skirt the line, slowly developing arguably even more depraved genres; and on the other hand you'll have rulings against perfectly above-board, consensual pornography/speech, just because a politician doesn't like it (as have been attempted many times throughout history, and remains a concerted goal of the right to this day).
I have to assume this is what it feels like to be an old-fashioned puritan, seeing a clear line between pornographic content and the erosion of society. But in this case, I think that's where I am. I just don't think it's ok for the future of society to normalize artificial CSAM.