eating meat is morally indefensible isn't it. when you think about it for a moment. there's no way to actually morally justify it.
You could argue that biologically, we have evolved with a capacity/need to gain certain nutrients from eating meat. The B12 thing is a medical issue in our house that is resolved by food supplements and occasional injections (like twice ever). The same is also true of carnivores too. “How do you know you’ve had enough protein?“ gets the response “the same way you know you’ve had enough potassium!“
Greg Wallace discussed a few years back how we’ve gone from people literally dying of malnutrition to obesity in cities in UK in just over one generation. He suggested the availability of cheap meat was a good thing for health of poorest people and solution to obesity issue is to find a new happy medium and not dismiss the benefits of cheap meat. I hate Greg Wallace but think it’s an interesting discussion in contrast to tax-the-poor millionaire Jamie Oliver.
Also, I love walking up the hills and when you realise that almost all of our “natural“ landscape has been designed to breed animals or birds for either eating or shooting then it does make me a little more sympathetic to eating meat as part of a sustainable local economy (not that this couldn’t be changed over time if the public will was for that to happen).
Of course none of this really stands up when one understands the brutal and sadistic nature of mass-produced industrial meat production (why worry about your B12 levels if the bacon is giving you cancer) but they are arguments to consider if/when meat consumption decreases.