Tonga votes against equality

Radio New Zealand reports that on Thursday the Tongan Legislative Assembly - all but one of them a man - voted 18 - 1 against ratifying the Convention on the Elimination of All Forms of Discrimination Against Women. The Convention is one of the most widely-accepted UN human rights conventions, even more widely accepted than the Convention Against Torture or the ICCPR; only eight countries (including Iran, Sudan, the US, and of course the Vatican) have refused to sign it. It commits its parties to ending discrimination against women in all its forms and:

(a) To embody the principle of the equality of men and women in their national constitutions or other appropriate legislation if not yet incorporated therein and to ensure, through law and other appropriate means, the practical realization of this principle;

(b) To adopt appropriate legislative and other measures, including sanctions where appropriate, prohibiting all discrimination against women;

(c) To establish legal protection of the rights of women on an equal basis with men and to ensure through competent national tribunals and other public institutions the effective protection of women against any act of discrimination;

(d) To refrain from engaging in any act or practice of discrimination against women and to ensure that public authorities and institutions shall act in conformity with this obligation;

(e) To take all appropriate measures to eliminate discrimination against women by any person, organization or enterprise;

(f) To take all appropriate measures, including legislation, to modify or abolish existing laws, regulations, customs and practices which constitute discrimination against women;

(g) To repeal all national penal provisions which constitute discrimination against women.

Specific measures include ending discrimination in political life, education, employment, citizenship, healthcare, and marriage, and to ensure equality under the law.

I'm left wondering what part of this Tonga's "leaders" objected to. Are they so medieval that they'd vote against simple, basic equality?