There was no attempt by scientists to create beneficial mutations. It was simply a fact finding mission that as a side benefit proved that small changes in a gene can produce large morphological changes. The researchers knew the mutations they were producing would likely be nonfunctional and probably detrimental in all cases, simply because of the size of the change. They used what James Watson (from Watson and Crick fame) called 'macro-mutations' simply because micro-mutations would result in morphological changes very small and difficult to see. This shows they were not concerned with producing viable morphological changes. Your criticism is unfounded.
"Fruit fly experiments, in fact, due to their utter failure to create an advantageous mutation, actually hurt Darwin's theory.
They did no such thing. They produced what was expected and more. We don't need those particular tests to show us that beneficial mutations occur and can produce morphological differences large enough to warrant the conclusion of speciation. Evolution does not expect speciation to result from saltation events (which is what those large changes are called).
"But, like the fake moths and the finches that didn't really change, they're all ya got. Sorry.
The only thing fake about the moths was that they were pinned to the tree so they could not fly away before pictorial documentation was finished. The part that applies to evolution, the change in colour as produced by selection was not faked in any way.
The finches did change. Size and beak shape were affected by availability of food type. This is part of the original formulation of the Theory of Evolution. The ToE states that all change is the result of variation in inheritable traits that are filtered by selection. Since Darwin's time this definition has been expanded and modified to be more accurate, but adaptation to environment is still part of evolution.
But the finches were still finches.