We are not talking about posting questions or answer choices written by ACT, but essays written by students. Does ACT hold a copyright over the essays students write? Do students sign a statement giving ACT the copyrights to their essays?
An essay written by a student seems to me his or her own intellectual property. Forbidding the publication of an essay by the essay’s own author looks to me not like test security but a coverup of sloppy scoring procedures. Essay topics are not recycled.