“poorly planned vegan diets that do not replace the critical nutrients found in meat, can lead to serious micronutrient deficiencies.” (from the article)

Yeah, switching your diet to anything has that risk, obviously. You need to understand what you eat.

And your daily life is already supplemented with pills, the only difference is they’re given to the animals you eat. Cattle is given B12 because they don’t graze and don’t have access to enough cobalt.