Not sure about OS kernels, but their intent was to attract C++ programmers, although, they ended up mostly attracting python programmers.

You mean, if we assume that the word "systems" doesn't have a well defined meaning, that especially the Go team would know all too well when it used it?

I define "systems programming" to be programming which must interact directly with the kernel or devices. Doing so requires knowledge of how those systems work. It includes, but is not limited to, writing operating system kernels.