You need to have a hard look at your own life and review if there is anything you changed your mind about in your life when it came to preferences. You will find you sure as hell can change preferences and habits. You will also admit that the mind has a way of also getting stuck in a spiral where it can never come back from. These complexes or disorders can develop and reach a point of no return. On the other hand, some spirals of alcohol abuse, drug abuse, violence and so on can be reversed with concerted effort. The mind is much more pliable then you are willing to be honest about.
If it was so easy to change, don't you think more people would be "turning" straight? The majority of the homos I know would much much rather be straight.
Alcoholics don't like alcohol, they love the feeling of happiness the alcohol brings them; and how it makes them forget all of their worries. If they find something else to make them happy/occupy themselves they stop abusing drugs, alcohol, etc so much.
And the moment their new found distraction fails, or the moment they touch alcohol again; they're gone back to heavy bingeing.
Yes I could choose to sleep with women instead. But that doesn't change the fact that I find them physically repulsive. I find masculine figures attractive; thus I'm gay. I can't just choose to find females physically attractive.
There is nothing you can naturally do.
You can, however, take substances to alter your brains chemical makeup/how it behaves. You can dive into experimental mind manipulation to trick the brain. You can force a stockholm syndrome (personally my favorite type of experiment to play around with) effect. And some other things.
I will admit, the brain can be changed; but it's not so easy. It could take years, sometimes decades, to produce even minor results. And you do it by FORCING your brain to think different, you can't just wake up one day and say "I think I'll find women attractive now." And last I checked, being forced is the exact opposite of having a choice.
I will however, also agree that is can partly be caused by how you were raised/born as a child and what you experienced; because a child's brain is a lot easier to manipulate than an adult's brain (see above examples). But for the most part, it's just the chemical makeup of your body/brain that determines what you prefer.
Have you ever tried a food you've never tried before, and hated it? Did you decide to hate it before tasting it, or did you just tasted it and wait to see how your body reacts? Did you decided what you liked to touch, and what you didn't? Did you just say "I think I like the feeling of rubber. I think I hate the feeling of leather" without actually touching it to see how it feels?