by Ann Louise Bardach

About the author: Ann Louise Bardach is a contributing editor of Vanity Fair.

Freddie Rodriguez is discouraged. He has just come from his afternoon’s activity of trying to stop men from having unprotected sex in Miami’s Alice Wainwright Park, a popular gay cruising spot. Rodriguez, 29, is a slim, handsome Cuban-American with a pale, worried face who works for Health Crisis Network. “I take a bag of condoms to the park with me and I try talking to people before they duck in the bushes and have sex,” he explains. “I tell them how dangerous it is. Sometimes I beg them to use a condom. Sometimes they listen to me. Today, no one was interested.” Most of the men, he says, are Latinos and...