I admit that I am stretching the definition of "objective" recognized by the scientifically-oriented, but it is not contrary to much of thinking in philosophy. Technically, "objective" means other than subjective--other than individual opinion. It stands to reason that objective would exist on multiple levels--a universal level such as "2+2=4" regardless of time and place, and a cultural level of "in Japan one should bow" and "in Europe one should shake hands." These are not subjective norms but objective ones, even though we can find other cultures that have different norms.