This isn't a primary source (there are no links to the raw data for analysis) here so this post too is arguably misinformation, as it's selectively reporting findings.
I run a 4chan archive, fireden.net, I don't archive /b/ and my #1 reason I need to take down things is because of child porn, to the point that I honestly think about why i still run it anymore.
It feels like there is an impedance mismatch here.