If you look at the techempower submission source code you'll quickly see why: https://github.com/TechEmpower/FrameworkBenchmarks/blob/mast....
Pretty much every set of benchmarks out there is ruined by monstrous unrealistic code that squeezes out 5% more performance than actually well written code.
As a side note, one flaw of TechEmpower benchmarks is that to my knowledge they use the original "wrk" tool, which only supports HTTP 1.0 and is sensitive to "coordinated omission" [0]. This means it ends up being biased in favor of web frameworks that implement specific optimizations or have specific behaviors that aren't actually useful in a production context.
Or is it some Goldilocks not-unoptimised not-too-optimised I'll-know-it-when-I-see-it wishful-thinking thing?