Actually it sounds like y'all are blaming the wrong end of the political spectrum. Most of the water rules for distribution were written by politically connected ranchers and farmers, sometimes miners, to protect the financial interests of their industry back in the 18 and 1900s.

The rules divided up every gallon that flows down the watershed. The way the rules, some dating back to the 1800s, were written any retention of water on a person's property was seen as theft of water rights from the parties downstream. These rules were written a long time before the term environmentalism was coined.

Back when 'Whiskey's for drinking and water's for fighting over' pretty much explained it. It was all about water rights as a way of exerting control over business rivals. There were several brush fire wars fought over water rights as large ranchers, often with ranches the size of counties, and farmers consolidated their holdings and ran smaller outfits out of business.

You can complain about some liberal input into how the water is divided up presently. Environmental rules give the wildlife and fishes a cut they didn't get before, but the custom of having rules banning collecting water, including rainfall, predate the environmentalists by a very long time. The rules were ostensibly intended to keep people from damming large flows for commercial use but water rights were weapons. Often weapons of spite so the sloppy wording that technically bans running a rain gutter to a barrel may have been intentional.

Of course nobody in a very long time has been prosecuted for collecting rainwater according to an article I read. There are several businesses in the SW, one of which is run by an old hippie, that specialize in rainwater collection systems despite their entire business model being in violation of the law.

Ideally you could work toward getting the law changed. But if your just figuring to cast blame you need to direct your ire at a bunch of rich and politically connected farmers and ranchers who ran things a long time ago. Hippies and tree huggers had nothing to do with it.