I, too, have questioned the veracity of the life expectancy numbers, but for a different reason: Males typically do not become gay until some point after puberty. If the statistics for the general population include all childhood deaths, then surely some of those individuals would have eventually discovered their gayness. Or been indoctrinated, but that's a different story. The point is that any life expectancy survey conducted for this demographic will necessarily be skewed on the high side.
But, obviously, promiscuity in a homosexual context is a very bad idea. I've lost good friends to AIDS who got it that way.
In one sad case, a friend caught the virus in the early 1980s when he was very promiscuous. Later, he became monogamous and had a long-term relationship, living a quiet life on the Oregon coast. But it was too late, he was diagnosed with AIDS in 1994 and died soon thereafter -- a year before the protease inhibitors became available. This broke my heart. He was queer as a three dollar bill, as they say, and not the sharpest tool in the shed, but he was a nice guy, completely harmless. Regardless of the morality of homosexuality, no one deserves that. It tears me up thinking about all the other men who are still taking these risks.