The alternative explanation is that all those beginners have been told, for weeks and weeks, as they attend classes, that tango is a simply constructed walking dance with a few embelishments. So they pluck up courage and go to their first milonga, and lo, they find simple rhythmic music being played, and other people dancing a simple walking-based dance while making steady progress around the line of dance. No one is holding anyone else up, and they are greatly encouraged as they dance their first 2/3 tandas.
About an hour in, the 'beautiful people' arrive, all air kissing and expensive shoes. They take to the floor, and
don't walk. They stand and play footsie, in place, for so long, that the beginners, who have to resort to endless weight changes in place, because their teacher (who, it turns out is one of the 'beautiful people' too) hasn't taught them
anything that they can do without moving, have to give up and they go and sit down.
While they sit there, confused, they recall that the teacher refused point blank to teach
anything that wasn't based on walking (and in fact most of the lesson was 'just' walking), but no one
is walking, except the beginners, out of the door. Most of them will never return, and as the DJ having noticed that things have gone a little flat out on the dance floor, decides to play some alternative music, instead.
It's rather a shame that the 'beautiful people' didn't show the beginners, by example, just how satisfying a dance can be had from simple elements, used musically, to simple rhythmic music like Di Sarli. We could call it 'tango'.