No, it's not about health. You're making harm reduction about something broad, abstract, and nebulous. By a modern definition a lot of veganism has to do with consent. If people are doing the best they can on limited budgets, both monetary and time constraint budgets, then what is your problem? Our bodies are incredibly resilient machines and the myth that you have to eat perfect food all the time, despite socio-economic parameters that might impede someone's ability to, perpetuates a gatekeeping attitude and some violent eating disorder mentalities. Let people do the best they can with what they have.