Personally I think it's mostly a proxy vote against bigtech/social-media. People are pretty fed up with their practices but don't have power to act at a national level. But, they DO have power at the local level to show up to town council and talk directly (in-person) to their representatives.
I think the other side of this is that there's this old idea (mostly correct) that municipalities partnering with businesses is good for the community because it brings positive side-effects: jobs, more cashflow in the local economy, etc. This is much less true for data centers. It's just a building that uses power and produces heat/by-products. Generally, employment gains are tiny compared with the old "automaker" labor model of the 1960s-1980s
People recognize this and they're not happy. They don't think it's a good deal for their communities.