I don't think so. What seems more likely to me is that one or more of the following is the case:
1) The "fast-flux" nature of imageboards makes it difficult for law enforcement to effectively respond to illegal content hosted on them.
2) Deleting content upon reports places board administrators technically within the boundaries of the law.
3) The arm's-length separation between the owners of 8ch, the users who operate boards on the site, and the users who post content on the site allows the owners to claim a lack of responsibility for that content.
In that case, we're talking about something different though. Saying "they have CP" to mean "there is CP posted which then gets speedily removed by mods before LE can act on it" implies that AWS, Google, FB, Youtube etc also host child pornography. Certainly it will be uploaded and they will remove it.
Only when the platform embraces it does that statement make sense, which apparently 8chan did not if I understand you correctly.
I don't think so. What seems more likely to me is that one or more of the following is the case:
1) The "fast-flux" nature of imageboards makes it difficult for law enforcement to effectively respond to illegal content hosted on them.
2) Deleting content upon reports places board administrators technically within the boundaries of the law.
3) The arm's-length separation between the owners of 8ch, the users who operate boards on the site, and the users who post content on the site allows the owners to claim a lack of responsibility for that content.