That is very true. Caught a channel cat when I was younger on a piece of gum, I think it was Sante Fe...
I spent all winter throwin' Kastmaster's on the river and spraying them with WD-40. I took the leap after hearing the "myth". A buddy (who knows his stuff) confirmed that it doesn't work, so then I felt stupid. Who knows though, maybe it does somewhere?
Or at least once, at some time.
The belief about WD-40 as a magical bait persists. It has long been thought that it contains fish oil, which it does not. Supposedly, this non-existent fish oil gives it near mythical fish attracting qualities...
However, you'll look long and hard for evidence to support these fishy claims; I never found any. The parent company dispels the notion in all their copy, even sternly advising you NOT use it as a bait enhancer. But we keep on Believing.
This is proof that we prefer the lurid, inane lie to the mundane truth - something false prophets, politicians and other charlatans have capitalized on for eons.
As for what is actually in WD-40, here's the list:
Light machine oil
Mineral spirits
Chemical surfactants
Artificial fragrance
It was initially created as a corrosion preventive for missiles in the 1950's. The name derives from it's intent - Water Displacing compound, 40th attempt to get it right.
Since it is essentially a mildly toxic petro chemical compound, my suggestion is you follow it's maker's admonition and keep it AWAY from our waters - instead of hosing down lures and baits with it.
Indeed, you probably stand a better chance with gummy worms.