My thoughts
As far as American audiences being loud, it must be a regional thing. I have never been to a fancy theater, only big chain theaters, and I've never been in a movie where people were whooping and hollering and otherwise being loud. Very rarely there will be one person being kind of obnoxious, but I've never seen it like GOH's describing. The closest it's ever gotten was Black Panther, and when I saw that the theater was packed and there were maybe 5-6 people getting loud. I didn't begrudge them that in that movie though, because I know it had larger cultural import. Aside from that, the only time audiences really make noise is laughter, and it's got to be really fucking funny before people laugh loud enough for it to really be noticeable.