> But the verb "to be" is still special. Otherwise people wouldn't ask "who are you?" but "who do you be?". It's strange how it can be special in one sort of sentence and not special in another.

This isn't responsible for the "be not" argument, but it may describe the apparent unusualities over "to be." Our verb "to be" serves two distinct functions. It is the verb to exist, and also the copula (linguistic equals sign). This is an English thing; Not all languages use the same word for these two purposes.

"His name is Steve", and "I am over here" are both uses of be-exist, while "pie is nice" and "dear god, help me, I am on fire" are be-equals.

So "to be" is special in that it has a dual meaning which most people never even notice.