As far as i can tell, our "purpose" on earth is to reproduce so on that front I think homosexuality is some sort of mental illness.
I don't really care about any so called moral implications of gay buttsex, but there's no denying men who sleep with other men are still the largest vector of transmission of HIV. Imagine the catastrophic consequences of promoting homosexuality in a continent already ravaged by the virus?
http://www.cdc.gov/hiv/group/msm/
The overwhelming majority of those with HIV are heterosexuals. Also, most are from Africa.
HIV is not a gay disease. If gay marriage was legalized in the 70s and 80s, gays would be one of the least likely to get HIV.
Diabetes and obesity is worse than HIV. Physicians have said this. 3 months of treatment and HIV is undetectable in your blood. Those with HIV live til old age. They can have children. It's like they never had HIV. They can't spread it through unprotected sex.
HIV is a non issue to gays.