The bit that really leapt out at me was this:
Designers need to acknowledge that design cannot solve harassment and other social problems on its own. Preventing problems and protecting victims is much harder without the help of platforms, designers, and their data science teams. Yes, some design features do expose people to greater risks, and some kinds of nudges can work when social norms line up. But social change at any scale takes people, and we need to apply the similar depth of thought and resources to social norms as we do to design.
The point about social problems, such as harassment, is that they are social problems and, as such, need to be addressed by society as a whole. Looking for a technical fix for social problems is, at best, doomed to failure and may well end up doing more harm than good.