This is a name association mixup. Tom Whiting is well known for developing Genetic Hackle birds, because more has been written about him than anyone. That does not imply that the only chickens he ever bred were the Genetic Hackles. They are generally poor layers and you can't blame him for wanting some hens that were good layers. Since blue eggs are unusual, but otherwise don't affect the production capability of the birds, he set out to create a strain of egg layers that laid lots of blue eggs. The University of Arkansas did a similar thing, as well documented in other threads on this site.
So, the "Whiting True Blue" strain has no association with Genetic Hackle birds, other that that they were developed by the same breeder. I have never read anything about the True Blues being any better for fly tying than your garden variety barred rock. Someone may have started some rumors, we know the internet is great for that.