He is indeed! My younger sister feels especially strongly about veganism. She simply believes that, if one can live without exploiting animals, then it is unethical to exploit them, whether by eating them, using them for labor, wearing their skins, wool, or fur, or using products that have been tested on them. It's not for everyone, but if one fully comprehends that humans are animals, and that animals also have sentience/consciousness as we do (and there is no scientific reason to believe they do not), then believing they should be entitled to the same right to not be exploited by people as other humans are is not a particularly difficult ethical position to understand, even if one doesn't agree with it. She's also seen amazing health benefits from going vegan. Again, veganism is not something I personally would do, nor is their philosophy one that I agree with entirely -- though I do believe in the humane treatment of animals -- but she has a fair point.