I’m afraid the thread is somewhat misleading. China isn’t arresting writers for writing about homosexuality. China is arresting people who produce gay porn. Pornography is illegal in China and producing any sort of porn there can get you arrested.
To be more precise, from what I heard, writers and artists who were producing such content were uploading to a Taiwanese site called Haitang. Now in order to get paid, Haitang used some service from mainland China to pay the writers and artists.
So earlier in the year, someone in the police in China found the site and contacted the payment services for the contact information of the writers who lived in the mainland. A crackdown ensued and about 30 people were arrested. I think the current news stories are from the aftermath of these arrests.
Please correct me if I am wrong as I don’t really understand much of China and I didn’t do too much research.