Sir Charles Napier, a British general in India, said the following when Hindus complained about the prohibition on suttee (widow burning):

You say that it is your custom to burn widows.  Very well.  We also have a custom: When men burn a woman alive, we tie a rope around their necks and we hang them.  Build your funeral pyre; beside it, my carpenters will build a gallows.  You may follow your custom.  And then we will follow ours. 

Most cultures contribute some good things to the world, but some cultures are better than others.  Despite what the truth-is-relative postmodern crowd says, some things are always wrong.