1. You're not asking, you're demanding.
2. In one breath you claim that animal products aren't a natural part of our diet, but then advocate artificial (read, unnatural) substitutions. Your "logic" is inconsistent.
3. There is one logical arguement for veganism, but you aren't using it. First, you need to acknowledge that the NATURAL human diet is omnivorous, but because we have evolved larger brains (thanks to meat) we can circumvent that need using artificial replacements, in the for of supplements and fortified foods. I don't personally agree with that arguement, but I could respect it. However, I have no respect for morons who ignore science and insist that veganism is natural.