I think that's the operative statistic. If gay men were dying, they'd possibly tone down the ... well you know... at least, maybe for a while. If it's another std, and one that has a vaccine, it's just one more thing to roll the dice on.
Not all gay men are promiscuous, and not all promiscuous gay men stay do so for life, but the ones that do... they're already dipping their wicks in spots that carry HIV and other drug resistant STDs. Wouldn't be surprised if there are some bug chasers out there looking to get natural immunity out of the way early.