Just because something isn't a logical paradox doesn't mean it shouldn't be allowed to be called a paradox...it can also just mean "apparently self-contradictory"
Actually socioeconomic status was controlled for. What was not controlled for was pre-existing conditions that might make people have 0 drinks like previous alcoholism, medical conditions where you can't drink, etc.
I think all the things that dance brings to the table over the mean "exercise" are clear first-principles wins (using your whole body, listening and dancing in rhythm, listening to music, letting yourself go / being silly)