Same sex relationships were a real thing in ancient China. Emperors had same sex lovers, I know that atleast one had a male concubine. It was also en vogue for young noble men to have male lovers and at one point in time nobles having male and female concubines was common. There was a diety of homosexual relations at one point. That in and of itself says something. This went on for a long period of time. It was just followed by centuries where it was condemned.
Chinese history is long and has undergone numerous changes between ruling parties, religions, and customs. Just like with all other countries, when looking back at history, many things are shoved into the shadows unless you dig deep.