> The hurdle around assignment operator is as old as symbolic languages. That's why legends such as Niklaus Wirth wanted to use another operator, ":=", a notation that is still being used.

Well, sure; but more generally, the ability to accept other meanings for symbols (and keep subtly different symbols straight in one's head) is a mental skill, and individuals vary in their aptitude for it. (Presumably, this one is also relevant to natural language learning, since one must reckon e.g. with false cognates.)