Childporn seems to be the trigger here, but this is only the tip of the iceberg. This story illustrates a huge problem facing nearly all social media re child pornography. The laws seem like bright line, but in reality they are no such thing. Nearly everything is a judgment call. Nearly every daily decision is based on vague and uncertain definitions.
(Fyi, I try to avoid the now-popular term "child abuse imagery" because that is both too loaded and too narrow.)
I teach the definition of child porn to forensics students because they will be running into it in the profession. It is massively complicated. My child porn lecture goes as follows: Here are the rules (cases, laws etc). Then I show a series of images and clips that, given the definitions we just went through, cause the cops in the room to reach for their handcuffs. Then I show where the clips are from: popular pg13 movies and TV shows, none of which would ever be considered illegal. I do this to illustrate the lack of bright lines, and how definitions and treatments change based on context.
To avoid uncomfortable discussions best done only in person, let me simply say that there exists a range of material at issue here, from 1 to 10. 1 is stuff that while it trigger flags clearly isn't illegal. 10 is stuff where there is no debate. The law declares everything above 5 a crime, but nothing below 8 is ever prosecuted absent political pressure (webeweb et al). To be safe, Google moves against anything a 3, as happened here. So there is a range of stuff, from 3 to 8, that may or may not be illegal. It will be deleted/reported by the likes of Google but will never result in prosecution.
This is yet another a horrible story of an artist suddenly finding himself in that gray area between 3 and 7. His stuff is probably not illegal, but nobody can say for certain. Google has chosen to run in fear, but we outsiders, most of whom have not seen the material, tend to side with the artist against the big evil corporation. And nobody want to speak openly for fear of the labels that attach. It's a messy area full of emotions and pitfalls. Society needs to address this problem.