How do they know that the distribution of these images took place? How did that even affect them in their life?
I honestly doubt that this is the case - and even then it would be only an argument against distributing it, not watching it.
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.