As odious as the content is, curtailing it gets into a mess of legal grounds which the parent comment tried to explain why they believe so.

I understand getting riled up because of the content's nature but you haven't improved the conversation by debating on what specific legal grounds this type of speech in the US should be curtailed by. There's no direct harm to a victim, if a film maker includes a scene of a CGI baby being raped (for whatever reason they do it, be it for shock value, storytelling, whatever) should that also lead to a prosecution? That's the point where finding a valid legal ground enters, just defining it by "I don't like it" is not a valid legal reason.

I'm not American nor a free speech absolutist, much much less trying to defend people looking at CP, but you do need strong arguments on what basis to make laws against this.

You asked.