I understand the claims, and I am not really disputing their claims. I just don’t believe that if they really won’t harm the coating, then they are basically water already. You are spending money for a product that will not perform any better than what you already have. And while the Apple Store may use Whoosh, Apple support clearly states use a cloth dampened with water only, as does every other screen manufacturer I have ever heard of. Also, I do not know how you use your cleaner, but never spray the screen. Again every screen manufacturer instructs you to dampen a cloth, and never apply liquid directly to the screen.
Whatever cleaner you use may be safe. It just won’t work any better than a damp cloth making it a waste of time and money. This is a case where the simple solution is actually the most effective and safe.
https://support.apple.com/en-us/ht204172
You can choose whatever method works best for you And I'm not suggesting otherwise. My Cleaning method differs from yours, but I also do use microfiber cloths as well. What Apple uses in the store and what Apple care suggests is two different things though. Whoosh is a safe Product for iPad displays, as that's how It's intended. However, AppleCare is only warning the consumer of the following from the link you provided:
Cleaning the iPad:
"Don't use window cleaners, household cleaners, compressed air, aerosol sprays, solvents, ammonia, abrasives, or cleaners containing hydrogen peroxide to clean iPad."
Basically it's advising the consumer to not use house hold products to clean your displays for those who might be ignorant. Furthermore, AppleCare doesn't suggest to NOT use products that are safe for iPad displays, because they can't speak for other third party manufacturers.
That said, you quoted:
"I would never trust anything except a microfiber cloth, dampened if necessary. Anything else is not likely to be any more effective without doing more to strip away the coatings already on the screen."
Which again is perfectly fine to use a microfiber cloth, but other tested products won't "Strip" away the coatings, especially if they are Tested and guaranteed like Whoosh and Clean Screen are, which are reputable. Regardless, The oleophobic naturally will wear off with general use, wiping with a cloth or intended cleaners. But I would not use a product that is questionable or if I was uncertain of it.
But I do agree to never spray any water/cleaner on the display of any electronic product, which also, the manufacturer on any display cleaning product should suggest this also. It's also overlooked, but important to read the directions.