I think you expertly summed up how I feel, much better than even I could.
My parents spanked me when I was little. They were both extremely savagely abused by their parents, and they were lucky to have any semblance of sense at all when they got out of those homes. Eventually they learned to use other methods, but I don't hold it against them that they started out with a physical discipline, as it was all they were ever taught. (I am also ridiculously close with them now, and they have been "THE safe-haven for" me for my whole life.) I didn't see my home as a violent home, but my parents were acting violently when they were hitting me.
I have a different perspective from that upbringing. I have the Internet and work in a library, I have endless resources to determine what is not only subjectively best for my child, but also what is objectively the least detrimental to children overall.
I am so usually very much "to each his own" about parenting (at least out loud). If you breastfeed or formula feed, I am unconcerned. Cloth diaper, disposable, cosleep, crib-sleep, babywearing, strollers, TV or no TV...I'm pretty apathetic, respectful. I have opinions, but not passions. Spanking is my soap-box issue, which is probably why I tend to get dragged into these discussions...and why they often turn into arguments. It is one of the subjects I have the most difficulty with when it comes to tact and knowing when to leave well enough alone.
I. just. don't. get. it.
I guess it depends on what you are trying to achieve. The use of the term "violent" is the context of spanking is provocative and it will put people on the defensive in much the same ways as telling parents who send their kids to school rather than homeschool are "institutionalizing" their children, or parents who don't feed their children a completely organic unprocessed diet are "poisoning" their children. You can make a case for the technical correctness of that particular kind of word usage but it is pretty much guaranteed to shut down real communication with anyone who doesn't completely agree with you.
Why not approach it in the same way as you approach your understanding of your parents wrt this issue - as they learned more they did better. You can use what you know to plant a seed for a better way, or you can beat people over the head with it and turn them away from your ideas.