I think the point is that certain core aspects of erlang are not a 1:1 port between the 2 VMs. BUT THAT DOES NOT MEAN that erlang cannot be implemented on the jvm, you just trade off one set of tricks for another. As long as the language is not compromised.
Notice how its written that in Erjang you just use shared variables to pass messages between two processes VS copying messages. There you go. If the VM handles thread safety for you, then what do you care that the variable is shared vs not shared or mutable vs not mutable (in the underlying vm)? Shared just means better performance. Wasent the whole point of erlang to let your VM handle sharing vs copying and isolating processes; while you code multi-processing, erlang uses whatever it wants for efficiency.
"If the VM handles thread safety for you, then what do you care that the variable is shared vs not shared or mutable vs not mutable (in the underlying vm)?"
Nobody should. Mutability or immutability is a property of programs, not languages. Some languages make it syntactically impossible to express mutation, but it's still all machine language in the end, which allows quite arbitrary mutation, so the only reason those languages can work is that they choose to refrain from mutation in their VM.
Notice how its written that in Erjang you just use shared variables to pass messages between two processes VS copying messages. There you go. If the VM handles thread safety for you, then what do you care that the variable is shared vs not shared or mutable vs not mutable (in the underlying vm)? Shared just means better performance. Wasent the whole point of erlang to let your VM handle sharing vs copying and isolating processes; while you code multi-processing, erlang uses whatever it wants for efficiency.