As I said about quality, the significance of that varies by the nature of your customer.
Animal feed grains do indeed require protein supplementation for healthy feeding to all livestock. Thats why protein components that are often not human-edible are mixed in. And so are human edible ones too. But that does mean that protein content is indeed a desirable feature of feed grains.
If a piece of land is not as suitable for, say, wheat, and is best used for soybeans of lesser quality according to market conditions, it does not mean that the land cannot be farmed for lower yields of wheat or for another crop entirely. If a piece of land cannot be farmed or profitably used in agriculture for anything but animal feed (which seems very unlikely to me), and if there is some limitation on animal feeds that reduce the market for them, then there would indeed be some environmental benefit to letting it lie fallow or revert to wilderness, though this benefit is probably bought at a foolish price.
And then there are the inputs that go into growing this stuff in the first place - fertilizer, water, fuel, equipment and labor - that is less available for growing human-edible crops, all of which are more limited than viable agricultural land.
I am absolutely not for banning or limiting beef consumption; beef is a good thing indeed. I am also absolutely not for government controls on these things either.
But facts are facts, and if one is to argue with the other side it is best to be scrupulously accurate. We will always win with the facts.
I see you live in California, so you are around a lot of agriculture -- most of the state is devoted to it.
Vast tracts of agricultural land in this beautiful state are not agriculturally viable for anything but grazing or growing of livestock feed. I'm related to about five generations of folks who've lived it.
The point it that yes, there is quite a lot of ag land whose most efficient use is in livestock or growing of livestock feed; whole areas in the area where I grew up that ARE cultivated are used to grow exclusively livestock feed because anything else wouldn't be profitable.
This farmer (a fourth generation dryfarmer of feed crops) who lived in one of those two small regions was so proud when he devised a way to dryfarm high-quality organic wheat (it was "organic" by accident, not design, but he pragmatically figured that it might be more attractive to buyers if they knew it was organic). Yet he ended up having to sell most of it as feed grain anyway because buyers were so skeptical of the inferior quality of California-grown wheat with regard to use in baked goods.