Hi, you do not have to use the curl | bash options, completely understand the concern (I am also like that), but we wanted to make it easy for those who like it easy :-)
It is completely open source, you can take the executables and run it yourself, compile it, change it, however you feel like :-)
If you do try it, let us know how it is, happy to get feedback!
Thanks for sharing, we created an open source that takes any cluster and checks it against these guidelines, check it out, hope you find it useful:
https://github.com/armosec/kubescape
There is also an implementation difference between the two, while KubeBench requires installation within the cluster, Kubescape runs as CLI from any computer using Kube API, so it can be added to any CI/CD pipeline very easily, also the latest version enables you to scan YAML files before you deploy them so you know early on whether you are compliant.