What's actualy pointless is how you say a pure color is holy damage. It says of a pure light as in 1 color. Not a purification light you cant say it's written that anywhere. The Light Reaver is doing holy damage which is purifying. Lightning is not holy it is quite simple.

How can you even come to the conclusion that to have something that deal holy damage you need a pure color ? Luminaire is damn green! It doesnt even have white in it in first place. So your saying something PURE BLACK would do holy damage cause it's one color ? Common on man i know you can think better then that. The Light Reaver is yellow/white. Also in FF games holy spells are not pure color. Pearl for example in FFVI even has shade of blue and black! Cure spell are also always of more then one color. So because a color is pure(ONLY ONE COLOR) doesnt mean that it's holy.

Luminaire is lightning thats quite simple really.