But guess what, YouTube knows most of the time exactly what videos are music, and what videos are targeting children, so in that case they would suggest to repeat those. For me, YouTube suggests I watch whatever, not just music or videos for children.
Another data point. Sometimes I like a video, and later when I am watching with friends and see it again, I watch it again to show them. Apply this to partner, roommates, family, etc.
1. Music, which often lends towards repeat content
2. Children as a demographic, which any parent will tell you will watch the exact same movie/show/video on repeat ad nauseam.
Because of these, it's likely that YouTube has found that repeats (in general) drive more engagement.