I would say the companies hosting this content share more than an equal amount of the burden.
Yes, this includes Kotaku here, whose article could have, and should have, been something on the level of the examination that, say, Dan Olson did on 8chan's content. That was an important article that highlighted the fact that the site was, yes, used to host images of child sexual abuse and it wasn't an exaggeration or smear campaign. This stuff doesn't just show up on the internet one day as though it were produced by some rogue AI that hates children, there are a lot of steps involved in its production and distribution even if most people rightly never want to encounter it.
That's the point that folks like Ostia and I are trying to make. This is what the article needed to be, because this shit is a lot more common than what people want to admit. No shit the editorial staff failed, because they didn't do even the most basic due diligence on getting an actual story out of the article.