Why is the second ionization energy of oxygen greater than that of fluorine?

Question

Why is the second ionization energy of oxygen greater than that of fluorine?

Answer 1

I would say the same reason that N has a higher first ionization energy than O. It's easier to remove an electron from an orbital that's doubly-occupied than from one having a single e-. The second ionization energy for O refers to that p3 electron; it should be harder to remove than the p4 electron (which shares an orbital with the p1 electron) corresponding to the second ionization energy for F.