Well, I'm ambivalent about the implied moral authority of the UN here. It's like female genital mutilation (or female circumcision): according to our principles, it's gross sexism, and I'm sure it violates the UN declaration. However, it is a practice that most women in these cultures actively participate in (they do the ritual cutting, and they consider it an important rite of passage into female adulthood).
Is it morally right for people in Western societies to impose their values and principles on these cultures?
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The UN's moral authority - or lack thereof - is not important in my opinion. The merits of the Declaration's list of "universals" can be considered independently of the UN.
And regarding imposition...
Unless you're rolling into a country with tanks and so forth or using economic bullying (or some other means of coercion) to alter the situation I don't think it's an imposition to suggest it's not a good, acceptable thing to cut women's genitalia or, to use my earlier example, enslave other people.
There are certain conditions in which human beings flourish - when they have clean water, nourishing food, sufficient amounts of rest, safety and so on. Different cultures will have differing ideas on what sort of food, how much sleep, the taste of the water, acceptable levels of personal risk, etc but the fact that we share a common list of physical dependencies for health and general well being should be uncontroversial.
Any cultural practices that declare one group of people (women, minority groups, etc) as undeserving of these things falls outside of the 'isn't it nice we're all different' cultural relativist envelope.
This should be the test in my view between a cultural difference and raw oppression that's sanctioned by tradition - does the practice deny one group access to the optimum available conditions while presenting no such barriers to another?
If, for example, the Contemplative Tobbaganens of the Isle of Alloyed Metals think that women should be kept in dark rooms for 23 of the 24 hours of a day, to accept this with a tolerant smile without criticism would be giving tacit support to the practice - a practice that would deny women their rightful access to the conditions in which people thrive.
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The US has cultural traditions too of course.
For example, it's traditional to underfund public schools in urban areas. It's also now traditional to treat drug related 'offenses' (such as simple possession of a non-sanctioned mood alterer) like the most horrible of crimes, worthy of lengthy prison terms.
Military aggression is also a part of our heritage - starting with the Indian wars and continuing to the present day.
Since these actions are elements of our culture and acceptable to many millions of Americans, should we take it all in stride and accept it as part of life's rich tapestry?
Of course, you see where I'm going with this line of argument.
Cultural relativism is a trap. Like many fuzzy headed ideas, it starts with a kernel of truth - you should not impose your values on others - winds its way through shadow haunted woods and ends up in murky territory where even the worst actions, so long as they're explained away as being a part of someone's 'culture', are palatable.
Some things are just wrong because people get hurt or killed or are forced to live truncated lives against their will.
This should be considered incontrovertible.
.d.