Water

IR’s México, warm and dry, it is a pretty safe bet that they’ll have evaporative cooling.

You are probably right. I bet it's the cheapest solution to run in an environment like that. It's absolutely terrible to use good drinking water for that purpose though. Especially in an area where it is scarce to begin with...

The alternative, without evaporative cooling, implies the release of pretty warm water. Which, if you go see has some damnning environmental impacts and can even be the limiting factor in say nuclear plants sizing.

Using direct flow cooling like that would use even more water than evaporative, and probably provide less cooling potential in general. That's in no way the only alternative though. Depending on how cool the hardware needs to run, they could use direct air cooling, closed loop coolant heat exchangers, or any number of heat-pump configurations (air to liquid, air to air, ground source etc.). Those require more energy, but would be the only right thing to do in an area with scarce water supply. They already use stuff like that in more humid and in colder climates.

Moreover, you talk as if the withrawal of information by these datacenter companies should be used as justification for “we don’t have the whole information why are you assuming the worst”. Thats a very flawed logic on itself but …well, look into some environmental history books and tell me what you see when companies use that argument as justification not to look closer.

Don't put words in my mouth like that... "We don't know, so why are you assuming the worst" is flawed logic in the same way as the opposite is. Excuse me for not wanting to mindlessly accuse people of stuff before knowing if something is actually wrong. Do I trust these mega-corporations? Not one bit. Most of them put profit above all else, including environment and even lives. But baselessly accusing left and right removes credibility from the real crimes. They should be held accountable, they should get investigated very thoroughly, and they should be forced to disclose information relevant to their impact on people and the environment.