People are born with a predisposition to sin.
Sin deceives them through their irrational emotions.
They soon come to think that their sin is normal and natural, and that they are not perverts badly in need of repentance from sin.
Sexual sin is, homosexual or not, unlike other sins. We are wired for sex and in the correct context it is something a man and wife share that can even glorify God. But sex not in the proper context still activates the brain hardware, the chemical signals that can even alter brain formation they are so powerful. What WAS to draw man and wife together becomes a drug of a different nature. Even an addiction in some. And, yes, in others a complete perversion.
I disagree (as do the Church Fathers). Sexual sin is just like other sins: a perversion or exaggeration of a disposition toward something good.