I think you're misreading it, but maybe I am. I think Venus is saying that non-consentual bdsm is abuse, the same way non-con sex is rape.

That is the truth of it for me; and maybe a lot of other subs. Many subs are subs from choice, from recognizing something inside them that wants to be submissive, at least part of the time.
Same thing with us pain lovers, I think. I choose to be 'punished' in ways that hurt me; I love the feelings that pour through me. But, if someone hurt me without permission, it would not feel wonderful, it would be abuse and/or violence.
In fact, as I have found out, a spanking from Mistress is a wonderful thing, punishment is awful - it hurts like hell!