I read that the original comment was laying the blame at the feet of individual consumer choices - implying that if people simply bought/consumed less of … whatever is causing the Colorado river to be depleted then things would fix themselves. And the reply is saying that there need to be explicit regulations to cause this, presumably because people have really no way to know the what environmental impact each dollar they spend has and where.
I read it the same way, similarly to PR campaigns that tell Californians to water their lawns less and take fewer and shorter showers, even thought that usage uses by far less water than ag or industrial uses.