HFT doesn't subset C++ nor does it ignore the standard library. Given you're totally wrong about one I'm not inclined to believe you on the other, and I have an examples from the standard library used in game dev eg atomics.
in release mode.
As for game developers, you don't have to look any further than Unreal, CryEngine or EASTL, or a couple of talks at GDC Vault.
So who's right?
Not using some or most of the standard library is precisely not an example of subsetting C++. Just because the C++ standard library has a hash table available doesn't mean that every project has to use it. Companies standardizing their own high performance data structures where it makes sense, and other things as well, is just something that happens and often makes sense independent of language.
Keep up the good fight! "Exceptions are slow" is a realy outdated opinion