I agree but i also wouldn't consider that to be on a level to be classed as such. Some people have a fetish for pain and sometimes will use small acts such as slapping or pinching in a playful way to even initiate sex. An ex of mine when we first started dating used to initiate like a lioness. I'm not big into pain my self but it'd get her in the mood and I was happy To reciprocate. you could even say I looked like a victim of domestic violence after the first few months from all the bruising but it was all in good fun and never an act of violence. There's a big different between an act of violence and simply rough housing. I think the intent behind the act is more important in some circumstances. A slap with intent to harm is definitely an act of violence but a slap with the intent of playful rough housing between two people who are OK with it is fine