Because it is necessary to develop a "theory of mind" to figure out why some entities behave the way they do. You'll encounter fewer surprises that way :)
edit: also, I have the battle scars from moderated a few niche online forums/properties that were mildly popular. People who abuse services are surprisingly tenacious and creative. If there is the potential to make money - even a little - you get abusers who are tenacious, creative and sophisticated
I don’t think anyone suggested moderating shouldn’t happen or that it isn’t hard. This situation isn’t the result of unpaid mods of a web forum - Google has incredibly vast resources at its disposal.
Unfortunately the devil’s advocate has brought us no closer to an understanding of the problems posed by OP: how to appeal an unknown violation, how to regain access to ones data, etc.
My point was not that I was overwhelmed or under-resourced: it's just that trolls/assholes/rule breakers force you to regress to "I know it when I see it" because they can break the spirit of the granular rules without breaking the letter. The solution is to make the "spirit" the rules (i.e. be super-broad about what constitutes abuse)
Why?