Correct me if I'm wrong, but this is how Window's ABI works. Even command line applications have to parse their arguments, and this is just something that C's runtime usually does before main (in contrast to linux ABI, where every process gets an argument array).
Pedantically, C’s runtime doesn’t parse the command line arguments, CommandLineToArgvW does, and that function lives in shell32.dll, not the C runtime (Nor is it dependent on the C runtime). Ofc the C runtime is free to ignore that routine and implement parsing itself using the results from GetCommandLine. Either way though, yeah, it has to parsed in the child process. But that isn’t a huge bottleneck.
