I may be being pedantic but I’d classify that as a “whisper network.” Whisper networks are more community/victim driven where blacklists are authority driven. That distinction might help with clarity since comics doesn’t really /have/ a central authority that can blacklist.

It's a bit stronger than "whisper network". While a whisper network exists, there's also "you're blackballed at company X". And with industry concentration, all it takes is pissing off a few people at each major company to seriously damage your career.