Hmm, I think there's some confusion about my comment here. I'll use your reference to veganism as an example. Individual vegans can choose a diet which, for themselves, minimizes the harm caused by their choices. But at a larger-than-individual scale there are those who recognize that reducing meat consumption means addressing the reasons people eat meat, and that in turn means things like (but not limited to) developing meat alternative products that satiate people's cravings for meat. So, while veganism may be a good enough choice for yourself, it's unrealistic to not recognize the reasons why people don't choose it and to not keep those reasons in consideration when coming up with a strategy.