…and you would be COMPLETELY wrong, Carla.
Where do all of those vitamin B12 supplements come from — meat? Nope, they’re grown in the lab using bacteria (from which ALL B12 is produced, even in the soil and the gut). So if a vegan is taking B12 supplements, so long as they don’t have gelatin or other animal products added to them, they are still vegan.
B12 is also readily available from non-meat sources, including some mushrooms and many sea vegetables. One of the best sources is nori — the seaweed that is used for wrapping many sushi. Also, if a person grows their own vegetables, or gets them from a farmer’s market where the produce isn’t over-washed, they will get trace amounts of B12 from the soil that remains attached to things like lettuce.
The body stores up B12 for many years, so between those sources, deficiency is very unlikely to occur, and easily prevented.