I'm guessing, but one consideration may be that they're afraid of "moral panic" from their non-porn-watching customer segment.
The situation is ridiculous, though. Plenty of companies, including Pepsi and other FMCG brands, car manufacturers, tobacco manufacturers, etc. advertise themselves with clips so sexualized they're borderline pornographic. The market doesn't seem to mind. Avoidance of porn seems hypocritical.
Journalists actively go out of their way to find adverts on controversial YouTube videos and then they email the companies involved as well as publishing it on their website to shame the companies who did not pull the adverts from YouTube.
The situation is ridiculous, though. Plenty of companies, including Pepsi and other FMCG brands, car manufacturers, tobacco manufacturers, etc. advertise themselves with clips so sexualized they're borderline pornographic. The market doesn't seem to mind. Avoidance of porn seems hypocritical.