General Brazilian
desrespeitar costumes
most common usage in contemporary Brazilian Portuguese
São Paulo
desrespeitar costumes / burlando costumes
urban usage, may also use 'burlando' for a slightly more colloquial tone
Rio de Janeiro
desrespeitando costumes / zoando com os costumes
more informal variant using 'zoando' in casual speech
Portugal
desrespeitar costumes / menosprezando costumes
European Portuguese may prefer 'menosprezando' for emphasis on contempt