A VM is not a VM. Just because a program’s semantics are defined in-terms of “a” virtual-machine (Java, .NET, etc) - it’s otherwise entirely unrelated to virtualisation.

It always kind of cracks me up when I hear someone having to explain the difference between between these 2 breeds of VM.

At one point back in school a friend said to me "hey, I can't figure out how to install and boot JVM on Virtual Box. I need to use it for homework in another class. Help me?"

I wish I had been able to explain it as succinctly as you. Instead I sat there laughing in the guy's face for a good minute, eventually realizing from his expression that he was being serious, which only made me laugh even harder.

I'm pretty sure the original comment was referring to both types iirc. But regardless of that they are most definitely not unrelated both are providing a virtualized layer for things to run in. Interpreted language VMs are running code for a fictional machine and system VMs are doing the same thing for real hardware which is why they are called the same thing.