They'll keep coming after meat eating with every angle - health, ecology, economics, emotional appeals - but humans can live a long, healthy life with meat in their diet. That doesn't mean industrial burgers daily or portions that look like a carnival hot dog eating contest, but 4 to 6 oz of quality meat from animals is healthy. I think the US especially would be far better served to appeal to people to reduce portio…
My personal opinion is that we're so growth and value oriented - and that's fundamentally incompatible with a healthy diet.
Look at CostCo! They have an amazing amount of fresh, healthy meats and vegetables. But you're still walking out of that store with a twelve-pack of fish and the barrel of cheese puffs you saw on the way out. The majority of Americans simply lack the self control. The food production companies know this and take full advantage of it.