The intent behind making a distinction between machine language and assembler is because one can offer a deeper understanding of what actually goes on at the lowest level of computing.
The way I would prefer to teach machine language would be to start from scratch. This means you would create and define a simple set of instructions in the context of an equally simple 4 bit processor the students would build on a breadboard out of simple chips. And, yes, the microcoded instructions would be coded by hand using a diode matrix.
I truly believe such an exercise has enough value that it should be the starting point of a real education in computer science.
From there it's on to assembler on preexisting processors.
The reason Forth follows assembler on my list is that you can easily bootstrap Forth from scratch on any processor. Building the language from scratch is, again, to repeat myself, a worthwhile exercise. You would use assembler to get started and then switch to the embryonic Forth to build upon that. At some point you write your own code editor in Forth. From there there are a number of interesting applications (PID motor controller?) that could be implemented with the language you just built from scratch.
C offers an entry point into a world of languages that look and feel like C. It provides a tool that is close to the hardware, yet high level enough to allow for much greater freedom of expression. Doing arrays in Forth is a very hands-on proposition. In C it's pretty easy.
Once you are good with C you can easily pick-up languages like Javascript and Python. Not the same thing but you "speak" the same words to the computer to achieve pretty much the same thing. A "while" loop and an "if" conditional are the same incantations.
LISP opens the mind to an entirely different paradigm. It is well worth learning. The same is the case for APL. I don't think of these languages as "career level" languages. That may have been the case ages ago. No longer the case. However, the perspective gained is invaluable. As we try to solve more and more complex problems the limiting factor might very well become our ability to express ideas for a computer to solve these problems. Having the perspective of languages such as LISP and APL makes someone realize there are other valuable approaches to solving problems computationally.
Finally, C++, well, it's the entry point into object-oriented programming.
This, BTW, was pretty much my path through computing. I can't complain.