To interpret Beauty's Gift as a story about HIV would miss the point entirely, although the HIV issue is highlighted. The story is an allegory for a higher awareness of women as people. It is designed to showcase various levels of misogyny, from the violence of Cordelia's treatment to Edith's violation by her husband, all the way down to the quiet, subtle misogyny of Doris's fiancé Selby.
This is true even in the title. By calling the novel Beauty's Gift, the implication is that the intent of the novel is the same intent of Beauty's departing words to her friends: Protect yourself from the dangers of systemic injustice. Although the women in the novel are faced with this theme by threat of death, the novelist includes Doris's example to help show that inherent mistreatment against women doesn't always show up in overt ways. Sometimes abuse and disenfranchisement can happen silently, when no one is watching, without the knowledge of the woman being mistreated.
So by that reasoning, the novel is a call for women to unite through empathy and compassion in order to spur each other on to have the bravery it takes to stand up against injustice, no matter what the cost.