It also has to do with the hypothesis of abiogenesis, not the theory of evolution through natural selection.
And if anything, it proves that that sort of abiogenesis is a dead end. The "junk" comes in when people try to claim that it showed a potential abiogenetic pathway.
Miller had to create an atmosphere for which, as it turns out, there is no evidence that it ever existed on this planet. He had to artificially trap the amino acids in one section of his apparatus. He only got a few of the twenty that are used in life forms, and the ones he did get were racemic mixtures, whereas lifeforms use only laevorotatory forms.
Even if we granted the presence of all the amino acids needed to build a particular protein, the fact remains that they aren't going to react spontaneously to do any such thing: all those polymerization reactions are reversible in the presence of water. Which means, they break up as well as join together, and just as easily.
You'd be as well off throwing a bucket of nickels in the air and betting that they all land heads-up as relying on such a "mechanism" as this to get life started. And Darwin has nothing to offer until you have something live that can reproduce itself.
A point too often missed in discussion.
In fact, I would assume that Darwin's concentration was on the effects of selection pressures after sexual reproduction had become a routine part of biological processes on Earth.
What the processes were before that remain virtually anybody's guess. Which is why Miller's experiment is useful. If nothing else, like Edison's research, it may tell us what didn't work to bring about life's origin.
Your point about the handedness of life's molecules is a valid one, but it also indicates that the opportunity for these molecules to get together and dance may have occurred even earlier in the time sequence than Miller and Urey had seemed to suggest.
If development in space is what gives amino acids their lopsidedness, then a method of surviving atmospheric entry must also be theirs.
Researchers and advocates are often challenged to reproduce such events in a test tube or laboratory. Well, no one has equipped a laboratory anywhere with more pots and pools and warm dusty corners than primordial Earth provided a few billion years ago! And it was in operation for a very long time! Moving continents apart by a few centimeters a year is nothing compared to coaxing molecules into becoming a junkyard umbrella.
Is it too much to ask that people actually know and understand the difference between evolution and abiogenesis before them wanting their opinion on the subject to be taken seriously?