To my knowledge, they don't monetize their videos. I think their main goal is to get sponsorships from ICOs.
I see so I understand now why they are making these videos.
They can make more money if there are ICOs that will hire them to create an attractive and encouraging video about them instead of monetizing it. Good catch that you are doing this job, I've seen people who are following some youtube personnel like these guys as guide to their crypto journey.