Only real photos and videos involving real minors is regarded as CP. The drawings in that thread are not legally regarded as CP in the jurisdiction where this website is hosted, so as long as it's relevant to the thread's topic we see no reason to delete it.
How the hell is a drawing CP? Do you also think violent video games cause mass shootings?
what were those drawings?
Wouldn't you like to know.
So if such images were anywhere but the designated fap thread you wouldn't immediately delete it?