go to the words.... everything we use to attract a fish which is not BAIT is by definition a "lure". Bait is meat or veg of some sort which has scent and is perishable, I think. A fly is simply one type of lure.
Then at some point, the BASCAR guys started calling their lures "BAITS" just to further confuse matters....
I think this topic has been crushed, smashed, beaten, and ground into the dirt a hundred times in the past.
To the simpleton, proof does not matter once emotion takes hold of an issue.