The paper is available (in HTML even) and much better: https://academic.oup.com/astrogeo/article/58/5/5.39/4159289/...
Where the danger comes in is that normally the Sun is so bright that if you mistakenly look into it your natural reflexes cause you to flinch away, prevent anything more than a momentary glimpse lasting fractions of a second.
During an eclipse the Sun is dim enough that you could stare at it without "visual pain" (for lack of a better term -- whatever you call something that is too bright) to such a degree as to cause instinctual look-away reflexes.
As a result if you were dumb enough, ignorant enough, or presidential enough, you could stare straight at the eclipse for seconds or 10's of seconds during totality. During that time it will not seem "too bright", but nevertheless your eyes will be focusing intensely damaging UV radiation onto your cornea, causing those cells to malfunction and die, which is what causes blindness.
That said, this is highly educated, rational crowd. I would not feel comfortable giving this explanation to a gathering of the general public because it can easily be misconstrued to mean "this guy says looking at the Sun during the eclipse is not as dangerous as everyone says it is" which has the exact opposite implication with respect to safety. I expect this is why the "looking at the Sun during an eclipse is more dangerous" meme got started -- it results in better safety.
Merely restating that the UV is still there contributes nothing.
The surface brightness of the sun is the same during a partial eclipse: each bit of sun is just as bright as if there was no eclipse -- there's just less of the sun visible. This is true in visible and UV, so the ratio of UV to visible light is unchanged. The problem is that everything gets darker, so your eyes dilate, which increases the danger. Also, partial eclipses are neat, so you're more likely to stare.
During totality, it's a whole different ballgame. You can't see the bright part of the sun, and all that's left has much less surface brightness. I think it's roughly comparable to the moon.
The problem is that there is so much invisible energy in proportion to visible energy. So blocking a large portion of the sun's disk, so your eyes no longer detect too much visible light, still allows too much total energy which fries your retina when focused into a very small area by your eye's lens.
If you have any reason to believe otherwise please share your sources.
What you are saying is wrong during totality on a total solar eclipse (not an annular one). Your reference to Trump does not apply since he was not in the zone of totality. Did you view the August 21, 2017 eclipse in the zone of totality with glasses on? If so, I feel very sorry for you, you saw nothing.
"When the eclipse is TOTAL, that is, when ALL of it is COMPLETELY covered by the moon, you can then look at it directly without eye protection. In fact, during those few brief minutes and seconds of totality, you MUST look at it without protection to see anything at all."
Im mildly myopic with astigmatism, but no abnormal blind spots afaik.
In order to keep from overwhelming the brain with irrelevant optical data, there is a lot of processing going on, and one of the things that happens is a filling in of places where there's no stimulus coming from that part of the eye. It's possible you have blind spots and don't know it. Also, only UV-blocking sunglasses will keep you from getting cataracts.