The same is true of the diagrams in IKEA instructions, but that doesn't mean that the human brain works with them in the same way as it works with human languages.
- do you vocalize an interpretation of the instructions?
- 3D projection in your head?
- What are the differences between seeing an object, hearing a word that represent it, reading the word? (Now thinking about sign-language, braille...)
I just picked an Instruction set to see, but realised I was already biased with the expectation I had of how I would decipher it.
That's just equivocating on the definition of the term "human language"; that's not what a linguist means by human language.
I.e. your argument isn't really that Javascript or C are human languages as defined by the linguistics professor but that he or she ought to augment or alter his or her definition of "human language" to include them.
It's not like he was wrong about this?