I understand what you mean by violence and I don't want to come across as a stickler just for sport, but if we are taking a hard ethical stance based on principles we need to be precise with categories. Two of which is most important;
1. category of animals include humans
2. category of violence include any suffering inflicted knowingly e.g. being overworked in a sweatshop, psychological violence etc.
If we accept above categories, our supply chain, not only for food but for pretty much everything we consume, unfortunately do incur violence on humans. As such, if someone takes a principle on requiring no violence against animals, they must also be concerned with everything they consume or use, not only what they eat. I am not saying they shouldn't not eat meat if they didn't do the other, I am saying they shouldn't claim a position from principle.
In fact if they made either these two arguments they would be perfectly consistent; argument of convenience "not eating meat is more convenient than not using an iPhone", or argument of priority "not requiring violence against other animals is more important to me than humans". But still they couldn't occupy a principled stance of no violence against animals.