@Tinuviel I also think this is a lot easier with novels and music than it is film/tv.
With novels, you can absolutely impact an author if they start spouting white nationalism. The boycott of the book will absolutely hit the intended target. I think back to Pantera when Phil Anselmo was talking a bunch of White Power stuff at his concerts. Dimebag and Vinnie Paul hated that he did this, but again, the core target was 4 guys and as a result the 4 guys got a reputation for one person's (some say 2, Rex) stances acting as a reflection of the whole.
HOWEVER, then you get to TV/Movies. No one is entirely sure who gets residuals for what, but there are a lot more moving parts. (exception: tour coordinators for bigger bands. Metallica has something like 20 semi-trailers of stuff, roadies, etc.)
Technically, you can try to boycott/harm Bill Cosby, but in seeking to make him feel an impact you're also potentially impacting the entire cast of the Cosby show. Weinstein/Spacey? You boycott them and it would cover The Usual Suspects, where likely ever single caterer to key grip aren't responsible for their actions any more than Kevin Pollack, Stephen Baldwin, Gabriel Byrne...
I think at the end of the day you're talking about attempts to turn public dislike/cancel culture/etc into reputational attacks that aren't truly a scalpel incising a cancer. The desire to affect the source of the dislike can often grow greater than the logic behind the attack vector.
Interesting headspace. Lots of gray area and things to think about.