My husband and I were both raised with meat as the main dish, every single night.
As an adult, nothing has convinced me that humans aren't meant to consume meat. But I have concluded that our standard American portions of meat tend to be much too large and that, as consumers, we ought to be more conscious of production practices (to the extent that we can afford to).
Our parents and grandparents seemed to view a meatless dinner as an indication of poverty. For my husband and me, a week without at least one meatless night indicates a lack of creativity and effort, with meal planning. Besides, we're Catholic and we try to be more observant than our parents were (easy for my husband, who was raised by Baptists! .) We like the Catholic tradition of abstaining from meat on Fridays, both to focus on the idea of sacrifice (meat being a very small one), and for health. (Although the Church doesn't expect abstention anymore, except during Lent.) Our crew of 3 teenage boys is actually excited when I make veggie lasagna or "Mexican Hoppin' Johns" (layered brown rice and spicy black beans, corn, tomatoes, peppers and onions - a variation of an old southern dish with black-eyed peas and okra).
But they're in the period of peak caloric and protein need, in their lifetimes. They play physically-demanding sports. They crave meat and are usually disappointed and carb-loading, if they don't get it. So, I try to offer smaller portions of meat, using dishes that mix in meat with other ingredients, instead of always having a slab of meat flanked by side dishes. Eating less meat affords us more choice about what meat we buy - although we still can't afford organic, free-range, grass-fed meat from Whole Foods.