If you need to denigrate pure context as "whataboutism", then maybe your core argument is trash?
I mean, sure, lets not build datacenters that are 100% evaporation-cooled into each desert-oasis.
But if general water availability is your concern, than datacenters are so far down the priority list that any argument involving them is just laughable. And if you are against datacenters, then find a proper argument instead of making environmentalism look stupid.