I don't think it's extreme to refrain from inflicting avoidable harm to others. In fact that seems like the least we can do.
In the vast majority of instances in our part of the world, a vegan diet is far more sustainable than one that includes meat, dairy, and eggs. It uses less land, water, and energy and has a lower impact on native wildlife. We're currently killing 10 billion land animals a year in the US for food. At that rate, factory farms are practically a given. There's no room to give all those animals the space they need, and if we did, it would probably have a devastating effect on native flora and fauna. Our appetite for fish is depleting fish populations in all the world's oceans. New methods such as permaculture and veganic gardening will further increase the efficiency of plant-based agriculture.
Of course, to be humane to animals requires more than giving them enough space. We've engineered food animals to grossly overproduce flesh, milk, and eggs. Chickens are designed to lay 20 eggs a year - enough to propagate the species - not 300 a year, which takes a terrible toll on their bodies. Cows naturally produce enough milk for their calves; through intensive breeding and constant impregnation, we coax up to ten times that amount from dairy cows now, robbing their bodies of calcium and increasing the incidence of painful udder infections. "Broiler" chickens and turkeys have been bred to be so top-heavy that they often suffer from organ failure or collapse because their legs cannot support their artificially huge bodies.
So if we were truly going to be humane to animals, first of all there would be no dairy or egg industries, because the only way to sustain those industries is to force the animals to overproduce milk and eggs, respectively, which imposes hardships on them. Furthermore, I don't expect dairy farmers to care for cows whose milk production has dropped below profitable levels; that's why they're all killed at four or five years old - even if lactating and pregnant with late-term fetuses. I don't think it's realistic to expect dairy farms to care for all the excess cows who are produced as a byproduct of yearly impregnation to keep the milk flowing; for one thing, the size of their herds would constantly increase.
I don't think it's realistic to expect animals to live long lives if they're being raised for food. They're all killed as soon as it's profitable to do so. No farmer wants to keep a flock of broiler chickens around for up to 10 years and then kill them. Also, instant, pain-free killing is easier said than done, especially when done en masse, day in and day out. People get sloppy. The constant killing makes some workers sadistic and callous. Killing one animal may have a terrifying effect on those not yet killed and on friends of the animal being killed. And so forth.
Are morals entirely subjective?
If so, then we have a convenient excuse for slavery, the subjugation of women, and any cruelty, including factory farms. Can we agree that we have an obligation to refrain from inflicting avoidable harm on sentient beings? That, to me, is a fundamental tenet of leading a moral life. It's a close relative of the Golden Rule. Of course there are dilemmas, marginal cases, life-and-death situations, but in those instances we still try to be compassionate, kind, and respectful as far as practical and possible. If someone simply must eat animals due to circumstances, of course that's understandable. But most people in this country eat animals for pleasure or out of habit, not out of necessity. In fact, many people get deadly diseases from all the meat they consume.
We have dollar menus because the government subsidizes the meat industry. If they re-allocated those subsidies to the fruit and vegetable industries, those disease-fighting foods would be cheaper, the market for plant-based meat alternatives would expand, the environment would probably be in better shape, and we'd probably be healthier as a country. Dollar menus are an artificial construct which are largely the result of the powerful (and corrupt) meat and dairy lobbies. Besides, those dollar menus are not necessarily a bargain; over-consumption of meat may contribute to obesity, heart disease, diabetes, and osteoporosis - and those are expensive as well as harmful conditions.
I don't think it's extreme to refrain from inflicting avoidable harm to others. In fact that seems like the least we can do. Saint Francis implored us to go beyond that and to actively help animals in need.
Veganism only seems extreme because we are so extreme in the other direction. We have a network of bloody, violent slaughterhouses that kill 25 million animals a day in the US and 125 million animals a day worldwide - not counting fish and other marine animals. That's extreme. Factory farms are extreme. Veal pens, grinding baby male chicks alive at hen hatcheries, stealing baby calves from their mothers, immersing still-conscious pigs into near-boiling water, breeding birds who can't fly or mate - that's extreme.
Why not aim high? I was able to stop eating animal products and there's nothing special about me. I liked the taste and feel of meat and never had any ill effects from it. If I can do it, so can others. In my several years of vegan outreach, I've inspired other people to give up or substantially reduce their animal product intake. Each generation finds vegan food a little less strange. Soymilk and veggie burgers are everywhere. Huge companies like Dean Foods, ConAgra, and Cargill are investing in alternatives to animal products. Vegan cookbooks are best-sellers.
When I talk to people during tabling or leafleting, I let them know that there really is no humane meat - especially if we expand the definition of "humane" to include the feeling in our hearts. Rather than look as animals at sources of flesh and secretions, why not look at them as fellow travelers on this earth, worthy of our respect and friendship simply because they exist, simply because their lives have meaning to them, simply because they are of the same Source, endowed with spirit and intrinsic cosmic beauty?
When I advocate a vegan diet to people, I nearly always keep them engaged; they don't shy away at the mention of veganism. Within the given time constraints, I simply explain why and how to do it, and straightforwardly answer any questions, concerns, or objections they may have. I realize that hardly anyone goes vegan overnight. I let people know that for me it was a four-year process that happened in increments, and that I had lots of skepticism and doubts at first, also. I also let them know that, based on my and many others' experiences, it is almost never as hard as they think it will be. I often suggest that people think of the animal product they can most easily give up or replace, and start with that. I make sure to suggest, with enthusiasm, that they try new foods, cuisines, and cooking methods. Most people who go vegan find that the diversity and pleasure of their diet actually increases.
I have no problem in general with bans on battery cages, less traumatic killing methods, and other animal agriculture welfare improvements. But I advocate following the golden rule, of being as kind as practical and possible, which means not raising animals just to harm and kill them. Why not be as compassionate as we can be? Why inflict suffering and death when we don't need to?
Yes, there will probably always be some people who eat meat. There are always some people who do everything. But do I have faith that we can end animal agriculture as an institution, at least in the developed world? Absolutely. Tastes are largely cultural and can change. Habits can be broken. Societal norms evolve. I urge everyone to set their goals and faith on high and to help hasten this compassionate revolution - which is already underway. Be the change you want to see in the world and then inspire others.