To be honest Wayne, I looked at the detail shots on your page two and even while you declare f/22 the winner in many cases, I clearly see that the part in focus is noticeable softer which is what it is about here. It's however possible something is wrong with my vision but I'll let others be the judge of that.
Sure, f/22 diffraction does make it slightly softer (so does f/11 being two stops past f/5.6, as is f/22 two stops past f/11), but the f/22 depth of field can improve the picture greatly (some pictures, depending). When comparing slightly vs greatly, you do sort of have to look at the whole picture, but greatly usually wins.
Do you remember the days of shooting ASA 10 Kodachrome? (10 as I recall, around 1960). We thought it was so wonderful, and it was wonderful, but some of it was because even bright sun required shooting not past f/5 to have any shutter speed at all. It was sharp film, but some of the effect was that f/5 also improved our lenses (those in that day).
Diffraction definitely exists, and DOF definitely exists, and they are definitely related, but I fear the whippersnappers today may not all have the experience to understand everything.
I said that the smaller the sensor pixels, the more important fast lenses become if you want to have some options left. Technically they could go as small as 1µ with those BSI sensors but they'll become severely diffraction limited. Resolution and detail would suffer when using too slow lenses. DoF has nothing to do with this; it's besides the point.
If you want to crop small or print large with such sensors, you have to be able to open up wide.
That's just wrong. Wait and you will be surprised by the truth. Or you can be surprised today if you just look around, at actual pictures instead of reading the internet.
Whatever the size of any imagined Airy disk, what we see depends on the size of the image viewed, whether it is resampled to 1/16 size to show near full screen on the monitor (when you see 256 pixels combined into one monitor pixel - do you really imagine the original pixel size actually affected the diffraction you can see?)
Or resampled to 1/2 size to print 8x12 inches (and you see 4 pixels in one, but which resample is still enlarged about 9x size, because that is what printers can do). Printing is the harder case.
The DOF AND Diffraction seen depend on the size of the image viewed, how much enlargement of the smaller film or sensor. Fuzziness shows bigger as we enlarge it. I think many people using DOF calculators don't realize the numbers apply to 8x10 inch image enlargements. Monitor images are much smaller (NOT 3000 pixels size), so DOF will appear greater than the calculator indicates. And diffraction will appear less. They look better on the monitor, and it is not dithered color either. The internet geeks don't care, they only see their little calculators, and imagine Airy disks being centered on pixels.
I show my crops on those diffraction pages, and they are quite extreme crops. The first page is 100% crops (except the f/40 ruler is larger, about 1/4 frame height). The second page is not 100%, but almost, it is a very small crop, FX is only about 2x 100% crop.