For grass fed cattle, the vast majority of said water is from rain that would have fallen on the land with or without the cattle. It's not generally municipal supplies of water in use for naturally raised cattle.
Would it really be though? From my experience, most of the anti-meat crowd is against all meat, for any reason.
As to alternatives for real meat not grown as animals... we don't even get micro-nutrients for baby formula right... I won't trust alternatively grown meat for a very long time. I and my brother wouldn't have survived on conventional baby formula... I have issues with just about everything outside eggs and red meat.
As for all beef being grass fed/finished... I'd be way more than happy to see it become the norm, exceptions for snowy parts of the year only. I'd like to see regenerative farming, which pretty much requires ruminant cycles, be the norm everywhere... we need more ruminants, not less imo.
The most vocal anti-mean crowd, perhaps. I eat only free-range, sustainable meat from animals that had a happy life outside, instead of being locked up into tiny boxes. A lot of meat comes from factory farms where animals are force fed in boxes and never see the light of day.
I don't have a problem with hunting, as long as it's done sustainably. I have no problem with fishing, as long as it's done sustainably. The problem is that there are too many people and we cannot possibly feed them all meat every day in a sustainable manner.