Good point
Then how does "seasoning" happen to a cast iron skillet?
And along those lines, I once watched a couple of welders up in the patch heat a steel girder up to "get the water out". And sure enough, steam started rising from that piece of steel and water started bubbling to the surface. How did that moisture penetrate the steel?
Not arguing; genuinely curious
Cast iron is metallurgically very different than anything used in guns, except Hi-points. The surface is really rough. It's easy to get oils to stick to it and if you use oils which will polymerize, you can build up a thick coating of that polymerized oil.
No gun will have a surface like that (except Hi-Points) so the oils will do a terrible job of adhering. Also, since the goal is lubricating, even if you could do that, you probably wouldn't want to.
When you heat a piece of steel with a torch, the moisture is actually a byproduct of the combustion. If you heated it by just placing it on a red hot anvil, you wouldn't see any water.
This is moderately easy to prove: if you heat up a bunch of steel and weigh it before and after, it'll be the same weight. If you could get it to absorb enough water that you could actually see water bubbling out of it, it'd be a lot heavier when "wet".
The closest gun steel will ever get to "pores" (other than Hi-Point) is the very tiny amount of peak-and-valley surface variation that even machined surfaces have. That's what boundary lubrication is for.
http://www.syntheticlubricants.ca/english/view.asp?x=966
But you are definitely remembering FL's claims correctly. They are part of the reason I have always had a dislike for that stuff. That is complete snake oil pseudoscience.
I say this once in a while so I can't remember if I've said it here recently or not, but in general, most guns we're familiar with are pretty forgiving when it comes to lube. You can get away with pretty poor formulations, and that's why FrogLube succeeded despite being mediocre at best.
You won't really see issues until you start seriously working some aspect of the lube, by doing something that tests that aspect. That could be oxidization, say: you leave the gun for a few months and see what shape the lube is in. FrogPaste and FireCanola do poorly on this. You could test it by subjecting it to high heat; FL isn't great here and I can't imagine Fireclean would be ideal although some people seem to do well with it in suppressed ARs so maybe the low heat resistance of Canola doesn't tell the whole story. You could test the initial lubricity and the corrosion resistance, and on that FL does pretty well. Whether that's well-suited to your applications, given the drawbacks of that product, is something only an individual can really answer.
Personally I just can't get into spending money on inferior stuff when motor oil and axle grease is objectively better in almost every regard, and about a tenth the price. Or in some cases less.
And I don't have to #### around trying to remove every trace of something else, and then specially warm my guns, and then wipe things off, and chant verses in sumerian, and whatever. I just slap in grease or pour oil on, and shoot.
Granted, oil and grease aren't as utterly non-toxic as canola etc.
Of course, non-toxic substances saturated with lead and barium compounds from primers and gunpowder are not what I'd call "healthy".