How very droll and condescending of you. The Golden Rule is to treat others how you'd like to be treated, so I can assume you want to be treated in a droll and condescending matter in turn, so allow me to oblige:

A: What is sin?

B: Anything that destroys and leads to misery.

A: Do X or Y actually destroy or lead to misery, or is it moral panic, pseudoscience, misery more caused by socially enforced guilt caused by the belief that X or Y is bad, some combination of the above?

[B and A engage in an interminable discussion, and eventually B's Heritage Foundation links are exhausted]

A: it doesn't seem clear that any of these things "destroy" anything, or inherently cause misery.

B: Well X or Y must be bad, because they're sin, so they seem gross and bad to me. There must be hidden detriments that scientists are unwilling to admit, or just haven't gotten around to proving yet. Just wait, when you grow up you'll think just like me.

A: maybe.

You sound like a sad sexless man.