Could it be that it’s just not as popular as one might think?
https://www.theverge.com/platform/amp/2018/6/4/17424472/yout...
https://www.washingtonpost.com/technology/2019/08/14/youtube...
https://www.rollingstone.com/culture/culture-features/lgbtq-...
The washingtonpost story can be proven false. Whenever I add the word lesbian to a video title traffic goes up 4x the average.
The everage article was interesting. Keywords trans or transgender could put the video into a more mature sexualized context. Most searches with that term probably have a mature/porn intent. It's one of the more popular sexual preferences by keyword search volume so the context of other words matter more.