It's not innuendo when you consider the inherent problems with benchmarks. Once you have an algorithm, it's so hard to define what an objective benchmark is that you should assume the implementation is cheating, even if you wrote it.
I say this from personal experience; in one case I was doing timing studies to solve performance problems, and wound up fooling myself by measuring the wrong thing!
In this case, is it fair to use SIMD intrinsics? It depends on what you're trying to measure. I think that's why "cheating" is in scare quotes, because what would be cheating in one context might be useful information in another.
For instance, if C++ is providing SIMD intrinsics, it's going to beat other languages, and if I just want current performance statistics, that's the question I want to answer.
If the question is, "what's the overall quality of the code delivered by the compiler / optimizer" then using specific tricks doesn't give me a good answer.