Why do we (humans) get sexual attraction from the things that we do, and when that inner sexualisation of concepts differs greatly from the norm, why is that?

I don't think we know yet exactly why it happens, but AFAIU the working theory is that the sexual map gets programmed into the brain slowly over time when the person is an infant - like from pre birth to toddler age is when most of the substance is permanently etched, though it further (slightly) evolves over the whole lifetime. The programming is being done by your own mind without you knowing what's happening, as just one part of the mind and brain developing.

So why does Adam have a sock fetish, or Betty find furries erotic, or Charlie fantasize about being drowned in yoghurt, or Dani get off to being choked or hanged, etc? For completely unknowable reasons, just like why Eddie prefers blonde women or Fiona is bisexual. The infant brain was processing an insane amount of data from the outside and the inside, from genetic pressures to lived experiences both minor and major, to feelings of comfort and safety or traumatic events. And SOMEHOW it decides to etch into the hypothalamus, prefrontal cortex, brainstem, spinal cord, etc a "stimulus-response" relationship which later in life you experience as "oh that's hot"

Maybe 6 month old Adam had his mom tickle him when she put his socks on. Or maybe Betty had nightmares and only felt safe going to sleep with her stuffed tiger, and maybe Dani got tangled in her blanket and was being choked a bit before being rescued and comforted. Who knows, like it's impossible to ever find out for sure.

But you shouldn't feel like a bad person for having a weird sexuality. You're a bad person if you do harm to others, not if you're a bit weird. If you're a pedo but you never harm a kid, then you're not a monster, just someone with a wonky brain and a moral responsibility to never act on your urges. It's really easy to be self judgemental about being into guro or whatever, because the world is full of hateful people who like to punch down on people who are different, and because it's OBVIOUSLY super super weird to anyone who isn't into it.

But humans are weird, there is no "normal", everything's a bell curve and life is too short to hate parts of yourself you can't help and didn't choose. You're only responsible for your choices, and nobody is responsible for your choices but you. Fantasy and reality are different and just don't act out your fantasies to kill or maim.

You can spend your life hating parts of yourself, or you can spend your life trying to repress and "pray away the gay" or whatever, or you can accept and live with it. Just remember that there's this psychological thing called "neurological habituation" where your brain needs increasing levels of novelty to get the same stimulus it used to, and since sexuality needs an element of novelty it's easy to need ever increasingly extreme stuff to get off if you overconsume porn. Sexuality evolves slightly over life and experiences so don't get addicted into needing more and more for the same feeling as before