The problem is that cattle consumes orders of magnitude more water compared to plants, on top of the fact that they also eat plants, of which they convert a small portion of into (edible) mass.
Their urine, en masse, is highly toxic to the local environment as it kills plants (high salt content, fertilizer burn) and pollutes rivers (pH, over-fertilization, algae blooming).
It is true that lot feeds and industrialized cattle production create massive amounts of pollution but so does industrialized agriculture. The problem is on the how and not on the what (see Joel Salatin for a good example).
> The problem is on the how and not on the what
If we could realistically supply the entire demand for beef with cows grazing on fields on the same amount of land, without raising the price directly or by subsidizing the cost, I'd be all in. This is literally impossible as industrialized cattle production is that much more efficient, no matter how revoltingly disgusting it is.
I meet quite a bit of animal-activist types (by association) that 'expose' parts of the meat industry by taking jobs and secretly filming (as it's often illegal to do).
Most of the extreme horrors they've recorded are in slaughterhouses, but I have vivid memories of seeing cattle confined in small cages which fecal infected infections. Perhaps that's dairy production, as it doesn't affect the outcome (as much)?
Other than that, what you describe only applies to industrial farming, not grazing cattle. Cows graze pasture, they shit and piss in pasture, it's almost a closed cycle except for the added salt the herder usualy gives them.
What water claim? That cows consume water and excrete concentrated urine? I don't know what you're debunking without a source, but appears to be a straw man.
> industrial farming, not grazing cattle
Grazing requires orders of magnitude more land compared to cramming cows into small cages, which decreases the amount of food you can derive from this already (very) expensive food source.
I love beef, but that doesn't change the fact that it's an incredibly wasteful source of food and it ultimately unsustainable compared to plants, fish, eggs etc.