I appreciate you leaving spirituality and religion out of your response, since I consider myself an athiest and I don't believe it would have helped me to understand your position.
I believe that shame only specifically relates to bad actions. I believe that your characterization of shame as relating to morality is wrong. In your figure skating example, would you say that forgetting your choreography was immoral? Maybe it's just a difference between how we use our words, but I would choose to talk about just good and bad rather than morality in those circumstances.
As I understand your position, it seems that you are not against shame in general, but rather you are against shaming strangers. However, I have many enriching experiences of my own where I have been shamed by strangers. I believe that the most important factor is not whether the people interacting have a prior relationship, but rather it's whether the judgement and shaming itself is properly tailored and personal. If a stranger understands another's circumstances and thought process then I believe it's often perfectly legitimate for the stranger to shame them, specifically when that criticism strikes at the core of the other's mistakes.
In this particular situation for example, I would say that there isn't anything inherently wrong with slut shaming, but rather in order for any slut shaming to occur, there should actually be novel insight into why sleeping around would be bad, and should ignore or even compliment anything that is only incidental to the core criticism. Do you still disagree?