That data center started operation over a decade ago. There's no reason to assume it should have any vacancies currently, nor is there any reason to assume its positions were largely filled by non-locals. And even if a few external folks relocated in some cases, isn't that economically beneficial to the area regardless?
Also given the 24/7/365 nature of data center operation, the number of employees will be larger than the number of parking spots.
Meta says over 400 people work on-site at the Altoona facility [0], but most of those are clearly working for a variety of smaller contractors given that the initial tax terms anticipated a few dozen direct employees [edit: wrong state] and no datacenter companies show up in the county's 50 largest employers [1].
Also given the 24/7/365 nature of data center operation, the number of employees will be larger than the number of parking spots.