As someone who wrote a precursor to that code (I work on crosvm), any language other than C has to write binding code for KVM (or any kernel interface for that matter). Are you suggesting that the only language that should get to use KVM is C (and other languages that can consume C headers)?

Additionally, when KVM gets new features, the hard part will not be adding more bindings to that crate; it will be utilizing that feature, which would have to happen in any langauge.