> You're not doing a whole lot to explain why there is nothing wrong with eating meat and breeding cattle.

Why should explain why something is NOT bad ? It's up to you to convince him (or others) that it is bad, and the reasoning "according to MY ethics it is bad" is not a good argument.

There is a good argument to be made that in the West we should eat less meat, but that doesn't mean removing it completely: it is harder to make a balanced vegan diet, so for most people that would mean a less healthy outcome that just eating a moderate amount of meat.