It is the intent of this chapter to recognize the needs of citizens who are engaged in small-scale business ventures which could not be sustained if it were necessary to lease commercial quarters for them, or which, in the nature of the home occupation, cannot be expanded to full-scale enterprises. (Examples: supplemental retirement income, juvenile self-employment, single parents who must support and remain at home with preschool children, etc.) It is the intent of this chapter that full-scale commercial or professional operations, which would ordinarily be conducted in a commercial or industrial district, continue to be conducted in such districts and not at home.