Grain-fed beef, yes. Grain fed cows are not healthy cows. It's like when humans are fed a bunch of crappy food they shouldn't really be eating. What happens? They become sick, get fat, etc. Factory farming has made it commonplace for cows to be fed grain, because it is cheap and it makes the cattle fatter, therefore they produce more meat to be sold for a profit. This comes at the expense of both the cow's health and yours. But it's proven that grass-fed beef is just healthier. It has a far better omega 3 to 6 ratio, it is lower in cholesterol and saturated fat, and cows that are grass-fed are usually free of antibiotics and hormones.
There's a certain satisfaction you get from a nice juicy steak that you just don't get from nuts, pulses and so on. Also, as I have to continually remind a vegan friend, we would probably never have evolved our human intelligence without hunting. But I agree with posters above: try to stick to high quality meat where the animals are fed properly and avoid factory farmed shite.
I dunno, not all organisms who hunt develop a human level of intelligence. Think lions, foxes, eagles, sharks, even anteaters or venus fly traps (does that count as hunting?).
Hunting in packs is part of it I think. Although other animals do that, wolves being a good example, they are naturally equipped with sharp teeth etc for hunting. We aren't really set up like that. To catch animals requires us to develop techniques, strategies and so on. Apes are mainly vegetarian, if you discount insects. Perhaps when proto humans began to hunt animals, it led to the need for abstract thinking. Either way, early humans were certainly hunters. Historically, we know of very few vegetarian cultures.