I'm not really sure what to add on the topic. We've seen a number of cases in which, either through what you might call savvy gaming of algorithms or, in some cases, just brute force, people have been able to manipulate things such as trending topics.
One study that was done of fake news leading up to the U.S. election found that there was actually a small group of writers in Macedonia producing content who managed to get it spread to a tremendous number of people, because they understood how the initial readers were going to interact with it and how that would influence how the platforms promoted that content. To my knowledge, I haven't seen that used yet on a wide scale for harassment of individuals, but the same technique certainly could easily be used.