Why does carrie chapman catt claim that denying women the right to vote violates the principle of democracy?

Carrie Chapman Catt - The champion of women suffrage in US rightly claimed that denying right to women violates the basic principle of democracy. The right to vote and equality are the basic pillars of modern democracy and Democracy means "govt. of the people", "for the people" and 'by the people' and we see women are people and integral part of society.