Do you think that people who survived child abuse are unable to use the internet or read media? It's easy to find information about specific examples of child pornography by reading public records of court cases, and people who have survived child abuse are just as likely to make use of the dark web or be aware of porn related maters as anyone else.
People who have been through such experiences typically have extensive and long-running contacts with the legal and law enforcement systems, and at the ry least tend to maintain an awareness of their original abuser's custodial situation.
Just as there are networks of people who like child porn, there are networks of people who monitor its production and distribution. A few unfortunate people go on to become consumers or perpetrators of abuse in turn because they are drawn seek out imagery of what happened to them.
Be aware too that in many cases access to child porn collections are not traded for money, but for the submission of new material, so the distribution of it directly incentivizes further abuse.