Subset of: How can antibonding orbitals be more antibonding than bonding orbitals are bonding?

Stability of $\ce{H2^{-}}<\ce{H2^{+}}<\ce{H2}$

Stability of $\ce{N2^{-}}<\ce{N2^{+}}<\ce{N2}$

Source: Online lecture Etoosindia.

I am more concerned of $\ce{H2^{-}}<\ce{H2^{+}}$.

Does any satisfactory explanation exists (perhaps which can be generalized) for it? That is to add electron in anti-bonding molecular orbital more difficult than removing electron from bonding molecular orbital?

Observation indicates that First ionization energy of $\ce{H2}$ is greater than electron gain enthalpy (magnitude).

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    $\begingroup$ Yes, that's a general rule that antibonding electrons "more antibonding" than bonding electrons are "bonding". $\endgroup$ – Mithoron Jun 10 at 12:57
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    $\begingroup$ @Jay As Mithoron mentioned, this may help chemistry.stackexchange.com/questions/4517/… $\endgroup$ – Rishi Jun 10 at 13:18