I'm not sure what led you to believe that the water is being put back into the ground "simply" or otherwise but maybe you shouldn't be acting like it's a non-is

I'm not sure what led you to believe that the water is being put back into the ground "simply" or otherwise but maybe you shouldn't be acting like it's a non-issue when you clearly don't understand the problem. DCs are pumping the water through evaporative cooling towers because the latent heat of vaporizaton means there's a huge amount of heat sucked up in the phase change from liquid to vapor. None of the water is being "put back into the ground" except maybe that used during flushing and other maintenance. "Dry" cooling exists, where there is a closed coolant or refrigerant loop run through radiators, but those require more power, which increases cost and limits how much power can be used for compute (but they also get the say "it makes us use more power, bad for the environment! We're being Green by using evaporative cooling!")