Channels can't monetize "Adult Content" according to "Advertiser-friendly content guidelines" from YouTube [1]. Each video I encountered was clearly marked by AI for such content. It requires human intervention to successfully verify a claim that the content is educational. I doubt most of these spam YouTube accounts are doing this. (I'm claiming spam because separate accounts are copying and pasting the same video descriptions.) It's sad to see really. Naked yoga is really great outside of this exploitation. Videos with no verbal instructions and non-instructional shots of genitalia kill the spirit of the practice. Such a shame.
[1] https://support.google.com/youtube/answer/6162278?hl=en