Someone who has the option to be nutritiously fed by non meat, non dairy etc products (due to the large options of various vegetables avaliable in supermarket), but now feels somehow righteous in proclaiming that this is a more humane option that eating meat due to a prevaling ignorance of human evolutionary history. For our ancestors, eating meat was not so much as a choice as a necessity - hence large amounts of energy spent on 'hunting' rather that the hardly sustainable 'gathering' of amounts of semi-nutritious vegetables etc of many pre-agricultural societies. It was almost impossible to eat enough veggies to survive. Extended hunting was not wasted energy, and undoubtably because of this, your ancestors were not vegan, as they would not survive long on the limited benefits of this diet (i.e. not long enough to reproduce...). Thus, vegans should never criticise their meat eating relatives, as, without these people, the 'option' of veganism would not exist, as no human would be around to have this choice. Of course you can still be vegan, but this is because of a history of eating meat and not as a workable substitute to it.
Vegan: The exploitation of animals for food is anachronistic, and veganism is clearly healthier, kinder, a better way of life etc.
More 'objective' thinker: Yeah, you can be vegan - but get some historical perspective! Veganism is only really a choice in contemporary societies. Ok i'm conscious and can reflect upon my decisions, but more so i am an animal, and don't just eat meant for irrational reasons - it offers long term benefits! Like still being around today...
By A-S