A number of years before I went NC with my FOO, although looking back, I was starting to come OOTF, my nm very cheerfully said "Well, I used to hit you, and it never did you any harm!" I was shocked that she admitted it but I see that her admission (she is never wrong and never apologises) showed how she truly believed what she said. After all, any marks and bruises faded. As she never accepted that I had any emotions, she never harmed them. For me, it didn't matter if it hurt, and I don't remember the sensation but, my goodness, decades later, I still remember the emotional pain these beatings caused. I was powerless, shamed and blamed and had to grovel for forgiveness for what I had forced her to do. BTW, I never got that forgiveness, it was just added to the ever-growing list of all of the awful things I did to my nm, because I didn't love her as she demanded to be loved.
So yes, spanking is abuse to me, but spanking by a disordered parent is so many more layers of abuse and those are what did the damage to me.
Sorry for the rant!