I suppose this ruling is the best (only?) way to combat those who deliberately buy cheap reading specs purely for close targets but as a spectacle wearer I can't help thinking it's also going to penalise older shooters.
Older people tend to be long sighted and often need reading glasses for short distances. Short sighted people don't need special glasses for reading, just one set of normal glasses for everyday use.
I'm quite short sighted so I wear glasses 99% of the time. By the description given I can see it might work for me for seeing closer targets by not wearing the specs for those but then I'd definitely need to put them back for everything else. For shooting I wear disposable contact lenses so I'm not about to start taking them out for different targets
I do seem to be able to squint down enough to see very close targets a little better though, which brings me onto my next point.
Older people are more likely to be long sighted but they're also less likely to be able to squint enough to make it clearer. The eye's focusing mechanism gets less flexible as we get older. So a shot up reducer at 8 yards is going to be a lot more difficult for an older shooter than a younger one.
Personally I'd have no problem with an older shooter changing specs between targets. Those who have a reading pair and a distance pair will be used to swapping them all the time in normal life. And as people have said, it's not going to be practical policing bifocal usage so those shooters may get an advantage in some circumstances.
Just my perspective (pun intended).