It's absolutely not a dishonest benchmark. This backend comes bundled with V, it's what it uses by default. That's how you get the end result binaries when you use V.
To the end user it doesn't matter how the binary was generated. Via LLVM or via a bundled C compiler.
The only thing that matters: getting that binary after compilation and getting it fast.
At this point, I'm sure you can find a justification for any kind of criticism anyone brings up, so I will stop bringing it up. Sorry for being a bother, and good luck with your Go clone.