The fan community should first and foremost make it clear that such content is unacceptable. They can start by having open discussions about the importance of respecting characters and not using them inappropriately. Fan communities can also work together to develop guidelines that prevent the creation and dissemination of such offensive fanfic. Additionally, they can support creators who produce positive and respectful fan content, and by doing so, shift the focus away from such inappropriate works.
The fan community should firmly condemn it. This type of content is not in line with the values of a healthy and positive fan community.