To play devil's advocate: child abuse is usually a crime without direct evidence. CSAM is child abuse but the perpetrator films their crime as evidence. Everyone else who obtains and keeps this material also holds evidence against themselves as the possession of it is the crime.
Now for real: People often do not care a lot about child abuse. It does not affect them as it happens in private where they do not see it. CSAM however does affect them as it makes the abuse visible and shows something deemed reprehensible. In a lot of ways people see themselves being witness (even indirect by purely hearing about it) to CSAM as the victim rather than the children who are harmed in the making and by redistribution.
My cynical opinion is that it is a lot more about social norms and feelings arising from the violation of these norms rather than the harm done through the violation of children.
> CSAM is child abuse but the perpetrator films their crime as evidence
This isn't entirely true. In much of the Western world – outside the US – CSAM (or equivalent legal terms such as "child pornography", "child abuse material", "child exploitation material", etc) can include text, drawings, AI-generated imagery, etc, which no child was abused to create, indeed the child depicted in it may be entirely fictional. Canadian law goes so far as to treat material which "advocates or counsels" the commission of CSA as CSAM - which the Supreme Court of Canada insisted (in the 2001 case of R v Sharpe) doesn't include mere political advocacy for its legalisation (as in e.g. the NAMBLA Bulletin), although some will question whether that insistence actually cashes out in practice.
Now, as a father of school-aged children, I find the whole idea of groups like NAMBLA rather abhorrent – but, I'm hesitant about the government making it illegal for people to express abhorrent ideas, because there are likely ideas which you or I hold which somebody out there considers abhorrent.
Fictional erotica portraying fictional children is not CSAM. There is no child abuse taking place as there is no child in the first place.
Conflating the two is 1. wrong as a matter of fact and ethics and 2. a great injustice to the victims of child abuse.
This is exactly what I wrote about in the second part of my comment. People see themselves as the victim of CSAM or proclaimed CSAM through being witness to it. In fictional works there is no child who could be the victim showing very clearly what these people are really about. They are not primarily concerned about children being exploited but they do not like the existence of such material as them deem it offensive to themselves.
CSAM is a very real crime; including cases where real children are not physically harmed but get sexualized through the composition of the material. It is a crime because it violates children, not because it is offensive to societal norms.
> Fictional erotica portraying fictional children is not CSAM. There is no child abuse taking place as there is no child in the first place.
That’s your definition, but it isn’t the definition many authorities/activists/etc use.
And I’m not defending their definition, merely pointing out it is a real live definition in active use
To clarify, I am aware you are objectively describing the legal situation. I am not making a legal, but an ethical argument. We seem to be agreeing.
There is even a Wikipedia article about the legality. It's quite complicated in a lot of places because people really like to ban it but it very much is free speech or protected artistic expression in countries that have these concepts: https://en.wikipedia.org/wiki/Legal_status_of_fictional_porn...
To be clear fictional pornography about real children has to be distinguished from fictional characters. Even when the depiction is purely fictional. Sexualizing real children is unacceptable.
Not every problem can be fixed by making it illegal.