Personally I have been vegan for a year and a half and its mainly due to the fact that I recognise the wrongness in exploiting sentient beings by killing them so that we can eat them, etc etc. Also the DNA of an animal is so close to a human that it could also be considered a form of cannibalism if you eat them (think about that the next time you eat a mouth full of animal flesh)
It was seeing chickens trapped in cages from birth till slaughter. It breaks my heart so I don’t meat anymore.
Edit: I disagree with you argument about cannibalism. Many animals eat other animals and the differences in the genetic composition in terms of the nucleic acid sequence is what you can consider small but it doesn’t amount to cannibalism.