I agree there is a frustrating tendency to get into deflecting blame and pointing at different things, the situation with water is perhaps not a great example.

If you focus on household water usage, you'll have many people oppose your effort because they don't want to take shorter showers or buy a new washing machine. If you point out that some corporation is paying pennies to drain an aquifer to grow a water-intensive crop like almonds in the desert, it's easier to get the political base to affect real change.

Basically, you can try to get the majority of people to choose the greater societal good over their own comfort and convenience (good luck, humans suck) or you can try to convince enough of them to not let the almond farmers continue pillaging the shared water supply, which feels more politically viable.