To address your postscript: "Dark Arts" was not supposed to mean "bad" or "irrational", it was supposed to mean "counter-intuitive, surface-level irrational, perhaps costly, but worth the price".

Strategically manipulating terminal goals and intentionally cultivating false beliefs (with cognitive dissonance as the price) seem to fall pretty squarely in this category. I'm honestly not sure what else people were expecting. Perhaps you could give me an idea of things that squarely qualify as "dark arts" under your definition?

(At a guess, I suppose heavily leveraging taboo tradeoffs and consequentialism may seem "darker" to the layman.)