There are many possible reasons for being vegetarian or vegan.
If the reasons are specifically ethical in nature (i.e. not limited to environmental or health reasons etc. but based on a concern for the possibility that animals have a rich inner experience and have the moral standing of humans), then it's definitely ghoulish for all the same reasons treating humans as livestock is ghoulish.
When I was a kid, I simply didn't think about it. I also simply didn't think about how some people ate species that I considered pets.
If the reasons are specifically ethical in nature (i.e. not limited to environmental or health reasons etc. but based on a concern for the possibility that animals have a rich inner experience and have the moral standing of humans), then it's definitely ghoulish for all the same reasons treating humans as livestock is ghoulish.
When I was a kid, I simply didn't think about it. I also simply didn't think about how some people ate species that I considered pets.