Comment by SpicyLemonZest

The entire concept of a "takedown request" is a compromise solution. Platforms would ideally like to be a public square, where third parties can say whatever they want and the platform doesn't have to do much about it. Copyright holders, revenge porn victims, etc. would prefer to hold the platforms strictly liable, because on the Internet it's extremely hard to actually find the third parties. So in a variety of contexts we've found it's useful to meet in the middle: platforms are exempt from liability, but in return they have to process takedown requests, unless the third party challenges the takedown and makes themselves available for possible legal proceedings.