Edit: I know nothing about their admissions process, only that they have one. Somebody's unimaginative I see. "Admissions" should be filling out a form including contact info, bank info and so forth, and then verifying that it's all true. What could they (or you downvoters) possibly have vested in restricting admissions in any way beyond that?
To conserve scarce resources? No, resources are almost limitless, because it's online, and lecturing and presumably grading are partially or fully automated, and there's no campus with spatial restrictions.
To make sure everyone pays their way? No, everybody does pay their way, and it's a non-profit.
To maintain an air of exclusivity? No, it's the University of the People.
To make sure the on-campus community is vibrant, diverse, and full of people with interesting extra-curricular interests and leadership skills? No, because again, there is no campus and no on-campus community.
To make sure not too large a percentage of enrolled students flunk out or quit trying? No, because who cares? Only elite colleges that care about an air of exclusivity, and they care in the other direction, i.e. they want you to fail out so they appear rigorous and demanding.
So yeah. ????