OP, "shame" is a huge issue. After being in therapy for many years it was a revelation to realize that all my problems (shame being just one of them) were *not* centered around my sexuality. I'd grown up feeling shame, having low-self-esteem, negative self-image, etc. And, yes, of course, my sexual attractions were apart of that, but there was way more to it. Being very *different* (in the way I felt and thought about things in general) from my parents and siblings, and the rural society I grew up in, also played a big part in it.
I don't know how it is these days but when I was growing up, being "shamed" was commonplace. Sex, of course, is one of the biggest "taboos" there is. The heterosexual normative puts it in a very weird box where we learn sexual feelings and stimulation are 'ok' in certain predetermined instances but not in others.
But the question I began asking myself, even as a kid, is "what is the big deal?" Ok, so certain thoughts or fantasies or touching myself in certain ways leads to a change in awareness, excitement, stimulation, arousal and ultimately a brief moment of 'curl your toes' ecstasy. So, how come this is a big deal? Clearly *everyone* has these feelings one way and another and clearly people enjoy sharing these feelings. How is it (my young mind wondered) this natural, human instinct (one of the few we have) gets so twisted up, convoluted, put in a socially prescribed box of what is acceptable and not?
Obviously this is a huge question that has to do with the history of human socialization (controlling the herd), human psychology and the depths of what it *means* to be human. Volumes could be and have been written about it.
Long story short, my 'theory' is that we (meaning human beings in general) don't really understand ourselves at the most basic and fundamental level. Sex is a 'big deal' because it is one of, if not THE, most powerful forces driving human behavior. It's right up there with 'the survival instinct' and intrinsically coupled to it on the species level.
But there is more to it than just propagation and the existence of homosexuality is evidence of this. I believe there is in us a deeply seated 'wish' for union; to become 'one with' a transcendent force. That is, a state of consciousness that transcends our human limitations.
If I'm at all right about this, what we find sexually attractive, what draws us, stimulates us and brings about a craving for sexual union with 'an other', is a kind of 'projection'. Speaking in religious/mystical terms, what the soul longs for is union with the Divine. But at the level of our physical attractions this manifests as a strong magnetic force drawing us toward an 'other' that embodies these pre-conscious "Divine" qualities. Thus, for example, we speak of "muscle worship" or what have you. Speaking allegorically, what we desire is union with "Apollo" (the perfected figure of a male God) or (if we are heterosexual, perhaps) "Venus."
So where does "shame" come into all this? Why is it "shameful" that I, being physically male, am drawn (allegorically) to "Apollo" and not "Venus"? Why does it matter what "figure" or "form" stimulates in me the desire for union, gratification, bliss and even love?
I think the simple answer is, it doesn't matter. The "form" is just a carrot on a stick projected outward onto the 'other'; what we truly desire is union with the transcendent, which is beyond any form. Sexual attraction is simply an externalized, physicalized manifestation of this inner desire to *become one with* something we don't understand and don't even know how to talk about. These brief moments of ecstasy we experience during orgasm are just intimations of a far more profound possibility: Becoming Eros, the body of Love.
Cf: Life Against Death
and Love's Body
by Norman O Brown.