Of course. I should know by now that a professional career in materials science, chemistry, and geology is utterly trumped by garage "experience" and word of mouth "experience." What was I thinking to challenge such hide-bound, entrenched, absolute stupidity? I grant that you have forgotten more about bicycles and their components than I will ever know, but about material science you know bupkis.
It is immediately obvious that you know nothing of organic chemistry: "some sort of mineral spirit, I prefer naptha." The two are different chemicals that happen to have similar effects on some materials. In point of fact, "naptha" has several meanings, none of them precise, and different in differing parts of the world.
Define "sticky grease." Very little is known about the substance in question. The fact that it is old means that it has lost volatiles, in addition to what ever else it may have been exposed to. That means it may be quite different from what it was originally. It may have broken down, or it may have polymerized into something more similar to glue than grease—or both.
Whether or not a hydrocarbon is soluble in alcohol, or partially soluble, depends on the hydrocarbon. Some lubricants are, others not, but there is also the possible surface effect to consider, and they are far safer to use than most other organic solvents.
Simple Green will attack many metals given sufficient time. Twenty-four hours is not sufficient unless heat is applied. It is far safer than most common cleaners when used properly.
As for your casual attitude toward safe practices, be aware that some things sold as "naptha" will pass through nitrile gloves. Carburator cleaner will go through them as if they weren't there, destroying them in the process. "Lacquer thinner" is a blend of whatever the manufacturer wants to put in, and many of its components go right through nitrile.
But don't worry, the long term effects probably won't show up for years, and they are getting much better at treating cancer, liver, and kidney failure. The effects on brain cells, however, are immediate and permanent.