Drug and alcohol addiction are instances of a strange class of diseases where the only diagnosis that counts is your own. Until you see the problem ,in all it's starkness, the necessary desire to quit the behavior is not generated.
Other than demonstrable instances of genetic/biological differences, I see a similarity in homosexual behavior. The difference is one of subtlety. Alcohol and drug addition tend to smack you up the side of the head with the problems they create, ex. loss of job, family, freedom. Homosexuality has its own support group that appears to validated your choice, at least in your own eyes. At some level you feel good. It's difficult to put all homosexuals in one basket. Some are promiscuous; some aren't, some are a drain on society; some aren't.
The problem, as I see it, is identical in all but expression to those hetrosexuals that find overriding personal validation through sexual behavior. Part of growing up for me was to realize that my value as a man did rely on how many notches were on my bedpost nor upon the acceptance of another for me. Homosexuals, like all of us, have to take an honest and courageous look into the motivations for our behaviors.
If they do and still consider themselves homosexual then more power to them. Civil unions may be an fair compromise. Just keep it between consenting adults and please keep your hands off the dictionary. Your right to pursue happiness does not give you the right to redefine words for the rest of us.