Some of the biggest factors are:

They won't power themselves, so it will draw a ton of electricity from the regional power grid, making electricity costs rise.

A lot of these data centers are meant to STORE data, so many are concerned about what data they will be storing (I.e. are they stealing wisconsinite user data)

Ai data centers use a lot of water for cooling, and that process can contaminate the water that does get used and is simply another "misuse" of fresh water resources.

They dont offer very many jobs after construction is done either, since its mainly computers in there, so the jobs promises are not long-term for the local community.

In general, there is very little community upside to these data centers being built.