Jackie's on the right track. NONE of us (At least I HOPE none of us) considers this "violence". Spanking is how we show love and affection, even when it's hard or disciplinary. Nelson Mandela once said "True love comes not from the closed fist but from the open hand". Welll.....
Seriously, though, spanking is NOT violence the way we do it, and I would hope even the harshest spankings we dish out reflect that.
I also agree with Jackie's assessment of F/F videos. As much as I enjoy videos, I have a hard time watching other guys do something I'd rather do myself. Call it jealousy, call it being greedy
By the same token, most spankees I know will tell you that "Mommy" ALWAYS hits harder than "Daddy".