However, I did not say that it usually led to conception. That is a distraction and a straw man. The ramifications when it does are far more reaching than the benefit we get from sex without commitment.You said it was usually a bad choice.
Not usually.
So what? The person who engages in out of wedlock sex would have never done so if their parents had not engaged in sex or if they just had not chosen to breathe.
There are other choices/actions that have a direct causal relationship to the negative things you mention. Out of wedlock sex does not need to lead to any of the things you mention.
Further, all of the things you mention may result from sex within marriage or a committed relationship.
I agree that all that I mention may happen even if within a committed relationship, however the risk is less while in a committed relationship (IMO, it doesn't have to be 'wedlock'...) than in random sex acts.