There's a sliding scale of badness here. The emissions cheating (it wasn't just VW, incidentally; they were just the first uncovered. Fiat-Chrysler, Mercedes, GM and BMW were also caught doing it, with suspicions about others) was straight-up fraud.
It used to be common for graphics drivers to outright cheat on benchmarks (the actual image produced would not be the same as it would have been if a benchmark had not been detected); this was arguably, fraud.
It used to be common for mobile phone manufacturers to allow the SoC to operate in a thermal mode that was never available to real users when it detected a benchmark was being used. This is still, IMO, kinda fraud-y.
Optimisation for common benchmark cases where the thing still actually _works_, and where the optimisation is available to normal users where applicable, is less egregious, though, still, IMO, Not Great.