"All items entered for the competition must be entered in the name of the person who created the entry."
If Allen had hired 100 humans to create images based on his prompt, and then submitted his favorite of those under his name I don't think anyone would consider that legitimate. IMO having Midjourney generate 100 images is no different: Allen did not "create" this art, it was created by Midjourney (and by proxy, by all of the artists it trained on).