I disagree. One can read without knowing how to recite the abc’s (ie alphabetic order), sure. But anybody that is a competent reader will have little problem learning the abc’s if they were forced to recite it for a test.

You claim to be a competent musician who doesn’t know scales. I can imagine half-diminished and other intermediate level stuff being non-essential but at the very least major and minor scale knowledge is needed to read music. Being able to sight read implies playing in all keys, which requires knowing the major/minor scales.