Skeptic here.

Many of them probably are. Individual EMF concerns are often debunked. It is possible but unlikely that all of them are categorically complete nonsense. But let's put them aside for a moment. There are real, known consequences of living next to a data center as implemented.

Coil whine from transformers, in audible and infrasound movement of air, has real known effects, as well as suspected poorly studied effects, on the human head & ear.

The fact that we're just allowing a data center that says "I'm out of power, let me use more", to run four extraordinarily loud, dirty airplane jet turbines at the middle of their property for power generation on an improvised basis. And then when we look at their operation in aerial photos, we see 36 jet turbines.

Any and all non-closed-loop cooling systems are an issue, especially when they pull from potable water or operate in dryland droughts. The ratio of wattage consumed vs water consumed should be instructive here.

The amount of money that is going into these things is obscene, and when they choose to involve local officials it is essentially buying out your local-level democracy wholesale. Total lack of regulation. Town council meeting videos where all of your supposed representatives are under NDA; Extremely blatant corruption that the state doesn't want to touch. Races to the bottom.

These things are designed to run basically as lights-off factories, with little to no local labor involved. While there may be some initial investment in facilities, that will dwindle. When they are simultaneously not paying taxes via assorted individual arrangements, and raising electrical rates, there's very little to recommend them to locals.

We have established no general rules as far as buffers. Large-scale construction in general tends to kill rural watersheds & aquifers in close proximity. The sound issue is real, the EMF issues may have some limited credibility, and well-water is often tragedy of the commons, all of which might be totally mitigated by a half mile or whatever of forest buffer mandated around a data center zoning.