It depends entirely on how the science of psychiatry defines a "disease". The problem is, they don't have a clear ideological framework to build upon, because current mainstream psychology has an incomplete and essentially unscientific view of the mind. Science should shepherd us through all the personal bias and superstition, but psychology has failed to do this for homosexuality.
No, I'm not a scientologist. I do, however, vehemently support the growing Evolutionary Psychology movement -- which is essentially an attempt to bring more science and biology back into psychology.
About HOMOSEXUALITY, it is very difficult to imagine that an aversion to the opposite sex would lead to lots of children. Yes, homosexuals sire and bear children -- but not nearly as often as heterosexuals do. So, from a purely evolutionary point of view, homosexuality is a kind of ailment.
But fortunately, pure Darwinian calculation does not have to determine what we call a disease. If it DID, getting a vasectomy would be considered sheer dementia. And, men who choose to use condoms would be locked up and medicated.
Homosexuality has very little to do with the "mind". It is a physical difference of the brain that appears to be mostly genetic in cause. I know that the "mind" is simply the functioning of the brain, but mainstream psychology has not yet accepted this: They are clinging to outmoded Cartesian ideas.
We observe homosexual behavior in other primate species. What is so hard to understand and accept that this is just a peculiar BIOLOGICAL phenomenon? It is not a "mental disease" for the same reason that having red hair or cleft palate is a mental disorder.
Yes, it has a great deal to do with the mind and being a homosexual appears to be a distinct mental burden in our society (and in most human societies in general). However, there are many coldly logical and scientific reasons to remove it from the DSM that have nothing to do with the anti-religious or pro-gay biases among academics.
Short answer: YES, it was right for them to remove this from the DSM.