There are cultural differences - the congregation in many black churches vocalizes during the sermon. I think it's a universal tendency with cultural expression.
American black churches are part of American culture and there's plenty of non-black churches where the laity vocalizes. People even speak in made up languages. Plus, google up Shakers, Quakers or one of these:
Not really sure which cultures you’re assuming aren’t that way - Asian and African culture don’t tend to have a lot of childishness either..