There are people who for various ideological reasons hate beef.
If the market demands more chicken over beef, producers are perfectly capable of making a switch.
Cows are able to make delicious beef from grass and thistles; that they are often fed other things is not a proof that eating cows is bad.
Don't forget that cattle agriculture can make rainforests into wastelands.
https://www.sciencedirect.com/science/article/pii/S095937802...
> If the market demands more chicken over beef, producers are perfectly capable of making a switch.
Depends on local laws. In Canada, you cannot simply switch to chicken. It is supply managed.
Indeed my cattle mostly eat weeds, and eat things my chickens can't really eat. I don't feed either of them mass-produced crops, which actually also have ecological consequences in terms of huge amounts of petrochemicals needed both to fuel tractors and combines and to keep fertilising, topsoil losses, the amount of herbicides and pesticides sprayed, and so on.