As the homosexual community becomes more and more engaged and participates in social media, online violence and harassment targeting the identity of the gay community become more frequent. In order to explore the causes of the stigma behind this phenomenon, this paper starts with the gender stereotype of the homosexual community and explores the roles played by the mainstream community and the gay community in the interaction of social media from the perspectives of the active side of spreading prejudice and the passive side of accepting stigma. The relevance of labelling theory to spreading prejudice and accepting stigma is also emphatically discussed by referring to the theories of previous scholars. In addition, this paper discusses how the gay community as a stigmatized community is affected by social media, which shows that social media can be a double-edged sword for gay and lesbian communities. On the one hand, online groups help increase collective self-study, but at the same time, they also face the risk of mental illness. Finally, suggestions on both population groups for de-stigmatization are discussed to provide ideas for substantive changes to improve the well-being of the gay community.