He isn't saying he can't imagine it, I believe he's saying there is no way that one can say they are living a moral lifestyle while still consciously contributing to the destruction of the planet and abuse of animals when it can so easily be avoided by eating different foods.
I understand some people can be naive of the issues or not be in a position to choose their diet.
I understand some people can be naive of the issues or not be in a position to choose their diet.