For example, in CO2, the molecule is linear and thus rotation about the intermolecular axis leads to an identical molecule. But if you consider the pi molecular orbitals, which are radially asymmetrical with respect to the internuclear axis, shouldn't the molecule produced by rotation around the intermolecular axis be different? And in a similar vein, shouldn't the lone pairs of the oxygens in sp2 orbitals be in different places once a CO2 molecule is rotated?
I was told I was thinking about the orbitals classically, which wasn't applicable. Could anyone expand on that? Or alternatively, is an answer like what's hinted at in the accepted one here along the right lines - essentially, the electrons don't matter due to their negligible mass so a rotation about the interatomic axis effectively produces the same molecule?