Fighting for democracy?

A new law signed by Pres. Karzai of Afghanistan has some troubling features. It relates to the rights of women in the Shi'ite areas of Afghanistan, and definitely takes away rights that were won in previous documents such as the Afghanistan constitution and the UN Human Rights Convention, giving women equality. According to the new law women must allow their husbands to have sex at least once every 4 days. The UN International Fund for Women (UNIFEM) says this "legalizes the rape of a wife by her husband." There are other aspects of the law that contravene international human rights and equality for women, such as that a woman cannot leave her house without the permission of her husband or a male relative, and this seem to go back to some of the worst practices of the Taliban era. But, as a whole the situation of women in Afghanistan seemed to have greatly improved in the past few years, including the education of girls and women and the involvement of women in business and politics. So the question arises, should US soldiers fight and die for a country that enacts such retrogressive and undemocratic laws.
Strictly speaking it shouldn't matter, because the Obama Administration has dropped many of the former Bush Administration's policies and catchwords, including the "war on terror" (while they are still conducting a war on terror) and the emphasis of sponsoring democracy in the Muslim world. According to the liberal interpretation of the Obama Administration, this smacks of American arrogance, trying to foist it's own system on others to whom it is foreign.
But, the question still arises, what is the US fighting for in Afghanistan if they stand by and allow the country to introduce undemocratic laws? And what is worse, it seems that this law was never actually discussed and passed by the Afghani parliament, so it was approved in a totally dictatorial manner. Surely even the Obama Administration must find this situation appalling and unacceptable, even if it is according to Afghani norms.
At the NATO meeting just held in Strasbourg, Obama defined the reasons why the US and NATO are fighting in Afghanistan. The first is to deny al Qaeda and other Islamist organizations a refuge where they can plot terrorist actions against local and American targets. The second is to support the democratic government of Afghanistan, and to this end the US has alloted m$80 for the upcoming Afghani elections. So it should be a case of putting your mouth where your money is.