Great questions.
Stigma, I think, would lessen if it were decriminalized ( look at pot for example - as to how something can go from taboo to socially celebrated).
I agree that some sp are just like therapy, mine is definitely one of them. Laughs, good music, great sex without complications. The great thing about some sp is they provide the GFE without the drama associated with an actual relationship.
Personally, I am not bashful about my playing; I even suggest it to my single pals!