It claimed the new rules were needed in order to "comply with the requirements of laws and regulations [and] fulfil the responsibilities of the company", as well as to build a "happy community" on the platform.
On Friday, Sina Weibo - a microblogging platform with almost 400 million active users, often described as China's Twitter - announced a "clean-up campaign" that would be removing "illegal" content, including "manga and videos with pornographic implications, promoting violence, or (related to) homosexuality".
But the decision appears to have been out of touch with the widespread growing social tolerance for LGBT rights in China's major cities.
In the past few days, a blog post (link in Chinese) with the title translated as "HelloSina scum, I am gay" went viral on social-networking app WeChat, even though the original post and its reposts have been deleted numerous times. "My son and I love our country", one woman in Shanghai wrote, as reported by the Guardian. She wrote that "Sina Weibo has discriminated against a minority group by associating gay people with pornography and violence".
Sina Weibo, which vowed not to target gay content on Monday, said (link in Chinese) that it "thanks everyone for the discussions and suggestions".
The affair has highlighted the cultural gap between younger Chinese more open to LGBT issues and "China's older generation - mostly very conservative 40-year-old men - who are now the main force of our society because they control the resources", Xiao Tie, director of the Beijing LGBT Center, told AFP, using a nickname.
The post stated that the site would be launching a three-month cleanup targeting "illegal" content, including images, cartoons and videos associated with homosexuality, pornography and violence. But Beijing's official stance towards depictions of homosexuality in the media is repressive, if inconsistently enforced.
Last month, a Beijing film festival pulled the Oscar-nominated gay-themed film Call Me by Your Name from its calendar without an explanation. "Social media used to be an open space, but in the past year things have started to change". The move sparked so much public backlash that Sina Weibo reversed its decision Monday, according to a statement posted online.
Rights groups warn that, in a culture that places a high value on filial piety, millions of LGBT people are still forced to live in secret with many marrying heterosexual partners rather than come out as gay. In addition to gay people, the country's liberals who were enraged by the crackdown also made their voices heard. "It's unbelievable to see this happen now, with everyone - straight or gay, celebrities or ordinary people - using the hashtag and joining in".