That post was filled with as much rubbish as the militant vegans spout.
The appendix is a vestigial organ, its testament that we evolved from organisms with a plant based diet.
Vegans don't need to get protein from supplements, the human body only needs around 60-80g of protein a day, which is quite easily obtainable through a balanced and nutritious vegan diet.
Supplements are not 'chemicals' vegan protein supplements are made from natural sources such as hemp or pea protein, sure it has to be processed but thats no more unhealthy than the hormone and chemical ridden meat we eat.
When you refer to 'draw nutritious proteins' I presume you mean complete proteins (those which contain all 20 amino acids), it is true that the only complete sources are not vegan friendly (meat, fish, eggs...etc) however all 20 amino acids can be found in vegan foods such as nuts, beans, legumes, eating a combination of these foods in a balanced diet will provide all 20 amino acids (we only actually need 9 from food, the body can produce the other 11 on its own).
I'm not vegan or vegetarian and can see how the aggressive or militant stance of some can wind people up, however don't mistake your dislike for them as a disregard for their lifestyle, it is and has been proven to be a perfectly healthy alternative to the common western diet.
I'm not saying it isn't a healthy alternative, I'm sure it has many merits. It's their righteous indignation against everybody else that gets on my nerves.
The appendix in other herbivores is much more prominent as it carries more of a function. In our bodies, it has been proposed that our appendicies are linked to diarrhoea recovery.