Whether homosexuality is a disease or not doesn't matter to me for the typical reasons. But it's interesting to think about, and I do have a few opinions.
There are good reasons not to call it a disease separate from all the political and activist posturing. Historically diseases carry stigma (they shouldn't, but they do). A couple hundred years ago diseases were thought to have not a single etiological cause, but to result from any of several sufficient causes that were associated with character or moral weaknesses. Even now physicians get lots of training on not making value judgments about patient behaviors. If they're 500 pounds because they have no self control, you don't treat them any differently. If they come in every 2 weeks with a new STD, you just give them antibiotics and some advice on how to avoid a future problem. But, this clinical detachment doesn't always work, and even for diseases with etiologies completely outside the person's control, people sometimes judge. To the extent that homosexuality has long been characterized as a disease as indicative of moral deficiency and weak character, it has rightly been removed from the DSM as a psychiatric illness.
However, I think there are still good reasons to call homosexuality a disease too. Sure, I'm willing to concede that there's no necessary psychopathology, but what about just plain old physiologic pathology? It's rare to find professionals who connect the reproductive system with reproduction, for some reason, but you can't reproduce with a gay reproductive drive without some conscious intervention. I'd say that qualifies it for most definitions of disease I've seen. And mitigating a disease doesn't change it's status as a disease, it just changes its status to "controlled" or "cured". For those (like me) who would prefer to be sexually attracted to women for purposes of procreation, having righteously dissociated homosexuality from disease status or pathology of any kind effectively eliminates my access to relevant medical or psychiatric care, a crime all on its own.
Professional medical organizations spend a lot of time lobbying for or against CMS (Centers for Medicare & Medicaid Services) designation of something as a disease because it always translates into reimbursement for medical services provided. For example, if obesity is a disease, you get reimbursed for someone coming in to your doctor's office and working out a treatment plan. If it's not a disease, you either don't get paid or you have to put down an associated diagnosis that is a disease (like diabetes, or high blood pressure, or sleep apnea). In the case of homosexuality, if I want professional help (rather than having a do-it-yourself and safety-be-damned attitude) I have to pony up the cash myself because everyone's so afraid I'll be stigmatized by being labeled as "diseased". For crying freaking out loud, label me and let me pay my $20 copay!!!
But, oh yeah. It's not about what's best for me. It's about pushing for civil rights. I'll just be a martyr then. Since I have no choice.