Of course sin exists. Opposite over hypotenuse. 
d’oh.
I think it’s an SDMB sin to bump a thread with something stoopid like I just did, but since it don’t exist, I don’t give a rat’s tootin’ ass.
Correct.
Social morality is not associated or dependent on religious beliefs.
Whether or not a society accepts or rejects a particular act should be the result of a common social preference, not the result of imaginary beings directing the fate of human beings.
There’s no “sin” because there are no gods.
There are immoral acts though, and it’s beneficial to society for an individual to adhere to basic societal moral principles.