There are rules, and there are exceptions. To make rules out of exceptions is madness.
Here's an illustration.
In Orthodoxy, you can have a former male prostitute who killed 10 people become a priest and even work miracles. He can even process with a myrrh-streaming glitter-bedecked icon through the streets and people will prostrate themselves to get a blessing.
In Idiocy, it is decided that the priesthood is a great vocation for all former male proestitutes and murderers and that glitter is good everywhere because it symbolizes the uncreated light. But eventually people stop prostrating themselves for blessings and there are no miracles.
Yet you and LBK have not illustrated how riza and precious stones on icons are an "exception" rather than the rule.
All that has been illustrated is LBK's ideas are closer to a little old babushka's piety and simple faith than to a deeper, more theological, more intellectual and more learned/informed piety and faith. The former isn't worse than the latter unless the former starts demanding that their faith is the norm, when it isn't and hasn't ever been.
I'm currently reading the Brother's Karamazov, and yes, it is fiction, but based heavily on Russian life at the time. I've seen a lot of this sort of "piety" being illustrated in the book, where the people refuse to question the Genesis story as being literal, or who think only in literal terms about the "faith of a mustard seed" passage. Such is a simple faith, usually by those who are earnest, good Orthodox Christians.
But, at the same time, faith and one's knowledge of the faith, and knowledge of iconography and hymnography should go deeper (if it can). Some have to stay on that basic level (otherwise, if seriously challenged, they lose their faith entirely), and that is fine. But they shouldn't demand that everyone remain on that basic, simple level.
It's like how we tell new converts about the unchanging Liturgy, how it is the liturgy of the ancient church and unchanged. Yet we know that it has in fact, changed, significantly. St. John Chrystostom would not be comfortable serving it today, though he'd find many aspects familiar (of course, especially his and St. Basil's prayers). Even more-so, St. Irenaeus and St. Justin Martyr wouldn't feel very familiar in our Liturgy today because of how different it is. It isn't like it evolved from the First Century to the Fourth and then stopped evolving. It continued to change and evolve. Same thing for our iconography. Someone from the First or Second Century may look at our iconography and won't recognize many of the elements within them, but could probably still see the influence that Jewish iconography and Early Christian iconography has had and that there is clearly a line connecting the two.