What does it mean "do not judge a book by its cover"?

Which excerpt from shirley chisholm’s speech “equal rights for women” provides support for chisholm’s analysis of how the facts justify her conclusion? `it is true that part of the problem has been that women have not been aggressive in demanding their rights. this was also true of the black population for many years. they submitted to oppression and even cooperated with it. women have done the same thing. `women need no protection that men do not need. what we need are laws to protect working people, to guarantee them fair pay, safe working conditions, protection against sickness and layoffs, and provision for dignified, comfortable retirement. men and women need these things equally. that one sex needs protection more than the other is a male supremacist myth. `it is obvious that discrimination exists. women do not have the opportunities that men do. and women that do not conform to the system, who try to break with the accepted patterns, are stigmatized as ‘‘odd’’ and “unfeminine.” the fact is that a woman who aspires to be chairman of the board, or a member of the house, does so for exactly the same reasons as any man. `as in the field of equal rights for blacks, spanish-americans, the indians, and other groups, laws will not change such deep-seated problems overnight. but they can be used to provide protection for those who are most abused, and to begin the process of evolutionary change by compelling the insensitive majority to reexamine its unconscious attitudes.