I don't think it is sudden, there was much of the same concern about Amazon warehouses and anything else that cuts down trees, disrupting wildlife, and human neighbors. The reason it is more of a concern with modern datacenters is because they don't come with a significant amount of new jobs for the communities they are affecting. People will put up with a lot if means their unemployed loved ones can get on their feet.

With AI being a looming threat to everyone's livelihood it is compounding the reaction, not only do these datacenters not provide new jobs, they are actively contributing to people losing their current jobs.

If these new datacenters were going into empty buildings in cities that already had adequate infrastructure, then no one would care. They would still be against ai in general, but the datacenters wouldn't be a problem.

edit:

They could probably get a ton of support if they went into one of the many cities with crumbling infrastructure, took over abandoned buildings, and paid to fix up the roads and stuff. Like if they moved into an abandoned factory in flint, and fixed the water supply they could be heros.