A spokeswoman said YouTube had already terminated accounts and whole channels, disabled "violative comments" and reported any illegal activity to law enforcement. The company only saw $8,000 in ad spending across the videos in question, the spokeswoman said, and promised to refund marketing money.

The response echoes what happened in 2017, when brands like HP and Mars pulled their ads after learning that their campaigns were running against clips that were either meant as child exploitation or included large numbers of pedophilic comments. The companies eventually returned to buying ads after YouTube appeared to have addressed the situation at the time, but it clearly didn't address everything. A surefire solution may be difficult. YouTube's content moderation relies on a mix of AI and human oversight that can't always anticipate shortcomings, and many newer videos are legal in and of themselves. It may need more aggressive monitoring if it expects to avoid incidents like this in the future.