Hoobajoob said:
Then why the rules against guro, scat and other subject matters in the first place?
In part, the art of a lot of them tend not to be good and they don't have any value outside of that fetish. A pretty low number of posts are rated questionable and explicit, and a lot of what falls under guro is general gore, because of how tagging works. As for that image, its definitely hardcore guro, but its not extreme in the sense that the TOS is referring to.
Again, its worded in an open-ended manner as well, leaving it up to discretion what constitutes its extremity and quality.
A good example is with furry. Some posts are allowed under that umbrella but the ban is there to prevent a much larger dirge of poorly drawn furry fanart with animesque styling.