Paladins are fuelled by their Righteous Goodness, but alot of their flavour is tied up with a deity (Atonement, Holy Champion, Divine Bond, etc...), even though mechanically they get nothing but a code and atonement from their deity.
Thus, we count Paladins among the roster of LG Deities' tools. The same applies to AntiPaladins in the CE Deities' toolbox.
Why wouldn't CG, NG, NN, LN, CN, NE deities want an equivalent tool?
If Paladins are fuelled by deities, as all their flavour points too, it wouldn't make sense that other deities would handicap themselves by not having these potent tools against their enemies.
If Paladins are instead fuelled by their supreme goodness, how do we not see parallels for supreme Chaos, Supreme Evil, Supreme Neutrality?
Thus, LG (and CE, and LE via archetype) exclusively having access to this potent tool is silly.