It makes more sense than deciding to delete over 100 videos of your best content for "their own personal stamp". They're there to make money, so they would only delete those videos if they absolutely had to.
You have to consider they deleted these videos right after the pornhub controversy, which means mindgeek was extremely frightened of anything not being age verified. It would make sense that they could only verify the ages of some of the models, and decided to cut their loses when other models couldn't be contacted rather than potentially get another lawsuit and be in legal trouble.