My dogs are both vegan. They eat a mixture of v-dog and natural balance (mixed 50/50). The v-dog has a lot of vitamins. It made their urine very very yellow and also made them need to urinate more often. I was afraid they may be eating too many vitamins. They do really well with the mix. I house sat my parents dog for two weeks, and he refused to eat his own food. He kept eating the vegan food, so my parents have switched him to a vegan diet. Note that my parents are not vegan, not even close. My dogs have tones of energy. They're both adult rescues so they were both on other diets before.
From the research I've done, and the stories I've read about many other vegan dogs, and from what I've seen with my own eyes, there's no reason to feed them meat. I can't justify killing one animal to feed another. The thought of that is ridiculous. Why is one animals life worth more than another?
Can't argue with you on the last point. However, I keep reptiles, more of a snake guy but I have lizards. Also 90% of the reptiles I have are rehomed, taken in because they have medical issues or they were unwanted. Lizards can not eat anything but insects, snakes can't eat anything but dead rats, sooo yea. Don't have much choice on that one.