This is so that control characters (and shifted characters — see https://en.wikipedia.org/wiki/Bit-paired_keyboard https://en.wikipedia.org/wiki/Bit-paired_keyb

This is so that control characters (and shifted characters — see https://en.wikipedia.org/wiki/Bit-paired_keyboard https://en.wikipedia.org/wiki/Bit-paired_keyboard) could be generated electromechanically. Remember a teletype of the era (e.g. Model 33) has no processing power.