It's interesting that meat-eaters love to reject veganism by pointing out that there are no absolutes, fundamentally misunderstanding what the true philosophy of veganism actually is. It's about reducing your personal contribution to unnecessary suffering wherever/whenever possible. Of course not everything is guaranteed unfortunately, but slow progress is better than no progress. Oh, and a vast majority of crop production is used to feed animals that we then turn around and kill to feed us, plus the additional crops that we eat as well; going vegan globally would drastically reduce that additional crop waste.