I mean it's generally bad form to attempt to explain why someone is of a particular orientation. You don't say "well you're only gay because you have trauma," because that's fucked up and overtly reductive of a key aspect of their personality.
I don't experience sexual attraction. I still get horny. Orgasms feel great. I get lonely all the time, and still need social interaction. My experience is far from unique amongst asexual people. I don't think it's as simple as a single chemical imbalance.
At the same time, I am scientifically-minded, and understand that my mind arises as a product of the processes of my brain and body. I don't disagree that hormones play as a factor in my orientation, but not everyone in the ace community shares that sentiment, and of course having your orientation chalked up to a specific medical or phychological "quirk" generally feels bad.