Because whether we're using tons of compute to provide value or not doesn't change that we are using tons of compute and tons of compute requires tons of energy, both for the chips themselves, and the extensive infrastructure that has to built around them to let them work. And not just electricity: refrigerants, many of which are environmentally questionable themselves, are a big part; hell, just water. Clean, usable water.
If we truly need these data centers, then fine. Then they should be powered by renewable energy, or if they absolutely cannot be, then the costs their nonrenewable energy sources inflict on the biosphere should be priced into their construction and use, and in turn, priced into the tech that is apparently so critical for them to have.
This is like, a basic calculus that every grown person makes dozens of times a day: do I need this? And they don't get to distribute the cost of that need, however prescient it may be, on their wider community because they can't afford it otherwise. I don't see why Microsoft should be able to either. If this is truly the tech of the future as it is constantly propped up to be, cool. Then charge a price for it that reflects what it costs to use.