Maybe you meant C++? You see no complaint because noone use that anymore. Anything that can be done with an easier language is done with an easier language. The hardcore C++ performance critical code is left to a few veterans, who don't complain.
I don't consider the combination of the C runtime + the machine model straightforward - just less arcane than C++. Consider pipelines and branch prediction and cache lines and it quickly becomes difficult. Granted, those typically become relevant later in the optimization stage than other things.
Pipelines, branch prediction and caching are not part of the C runtime. And unlike Haskell, C makes it easy to look at the assembly for a piece of code, evaluate it for the machine it's running on, and fix these problems when they come up. C is not generally adding additional burdens, especially not ones that a higher-level language like Haskell won't also be adding to a far greater degree.
Maybe you meant C++? You see no complaint because noone use that anymore. Anything that can be done with an easier language is done with an easier language. The hardcore C++ performance critical code is left to a few veterans, who don't complain.