I mean, what’s wrong with me and my wife unilaterally deciding to thwart God’s will and deny Him His right to join His creative power to our marital love-making?
Who in the hell does He think He is?
Well with that definition of sin that you hold I won’t even bother to argue about this.
In my opinion it’s at least as bad to discourage birth control when the result is an ever-increasing poor population. Though as I noted above, poor people seem to be pretty good at reproducing even without Catholic views on birth control.