>That's a weird qualification to me, as if most other vegetarians do it because of their religion.
Most vegetarians on the Indian subcontinent/Asia in general do not eat meat for religious/cultural reasons. Growing up in a Hindu/Buddhist-adjacent culture is often enough to cause someone to avoid red meat.
Buddhism isn’t so much veg like Hinduism. Lots of meat eating in Buddhist countries (Myanmar, Thailand) and even the monks eat meat if the elevation is high enough (Bhutan, Tibet).
Sure, there are plenty of meat eating Buddhists but there are plenty of vegetarian(ish) Buddhist schools as well. Full vegetarianism isn't as common as among Hindus, but restricting meat consumption to fish and poultry is fairly common (mostly among schools originally influenced by Chinese Buddhism iirc).
Most vegetarians on the Indian subcontinent/Asia in general do not eat meat for religious/cultural reasons. Growing up in a Hindu/Buddhist-adjacent culture is often enough to cause someone to avoid red meat.