The reason for this is that the lemon oil you use on your guitar is not actually oil that comes from lemons. Weird as it may seem, oil from lemons is indeed quite corrosive, especially to metals. The lemon oil you buy for your guitar is perfectly safe and actually protects the wood.
The moral of the story is only use lemon oil that is specifically made for guitars, as I suspect your d'Addario oil is. If you think that's too confusing, remember that if you have a tree that rosewood comes from (Dalbergia nigra for example), you'll never get roses on it.