Tim,
You're absolutely and completely right on one thing, old chum.
And that is that it's absolutely not about sexuality and that it is all about 'fitting in'. And just as you'd need to keep radical political opinions to yourself in the forces, or your deeply held belief in scientology, so too you may need to hide your gay light under a bit of a bushel.
The forces are inherently conservative (with a small c) and rely very heavily on an unusually high degree of cameraderie and cohesiveness. The successful soldier, sailor or airman should therefore be cautious about 'pushing' any unusual or contentious side of their personality or beliefs (even though this 'side' might be unexceptionable in civil life), and should introduce it to his colleagues carefully, or should avoid mentioning it, so that he can be sure that his colleagues can tolerate it. It's not about sexuality, but because the forces represent a unique environment (where you may be placing your life in the hands of your colleagues and vice versa) it is fair to expect the individual to "tailor his behaviour to suit the expectations and preconceptions of other people."
As Siseman says, there's no place in the forces for someone whose attitude is that he is: "not going to fit in and the rest of the world will have to dance to his tune."
That's fine and dandy for journos and civvies like us, but not in the forces.
A quiet, straightforward, non pushy gay man who wants to fit in and serve will be an asset to a squadron, as would a quiet scientologist or a former member of the Socialist Worker's Party. It's all about fitting in and serving Queen, Country, Service and Unit, and not one's own narrow self interest.
Enjoyed your Vulcan tome, by the way.