Front group lauds purported benefits of data centers without disclosing its backer.By Lisa SorgHENDERSON, N.C.—On a recent summer evening Mitzi Parrott, who lives in Vance County, saw a television commercial on the evening news that gave her pause. Kathie Hamm and Bobbie Lequire, also of Vance County, saw it, too, streaming on Sling and posted on Nextdoor.