Memes

I think anyone who has lived on or around a farm, or has just come to understand everything involved, would have a problem "admitting" that. Non-Factory farming in a modern country is dramatically benefited from having meat livestock alongside the vegetables, not to mention that there isn't really any better use for marginal land than to have farm animals like cattle on it. In fact, there are arguments that cattle on marginal land are better for the environment than leaving the land unused because they are better able to sequester carbon than nothing. The environmental discussion that is "clearly pro-vegan" requires bringing in countries that are downright backwards and use their behaviors to overwhelm the many countries where animal ranching provide overall benefit.

And there's as many Ethical arguments for meat eating as there are for veganism. The "big" argument for veganism here is the classic Utilitarian argument for veganism, but it has easily been beaten by Negative Utilitarian and straight-Utilitarian counters.

And since many of us aren't Christian or adherents to any Divine Command theory, "morality" is itself unethical and unsustainable to us.