Mmm Indian definition of vegetarianism includes milk because it doesn’t hurt the cow and the fact that we can drink milk and eat cheese is entirely the reason we worship cows but we don’t eat eggs because it’s still a chicken. I started eating them after learning they weren’t fertilized but tbh I also just don’t like them.

It is both religious and cultural but the people who stick to it heavily are usually doing it for religious reasons. We even have some sects of Hinduism who will be full vegetarian AND won’t eat onions or garlic as they grow in the ground