If the problem is that these companies are creating an externality by straining the local water supply, then maybe we should simply tax water more where appropriate? I don't think any sort of shame will be effective.

For the past decade water has been mismanaged in inefficient farming practices, like bad irrigation practices or production of alfalfa to feed foreign livestock. We also waste a ton of water on our big dumb lawns. "cooling datacenters" doesn't seem like that big of a deal.