I think most people do parallel in milonga because they have been taught, or learned that they were supposed to do lots of "quick" steps, or traspie as it is sometimes called. I always tell people they should concentrate on the strong 2 beats per measure indicated in the 2/4 time signature of most milongas. (This echoes what I heard from most most influential teacher.) Traspie, the quicks, are the icing on the cake, not the main course. If you make it the main course, then you have to leave something else out to make it danceable - "crossed system". People also say: "no ochos" in milonga, "no pauses" in milonga, etc. I disagree with them. Sure the musicians hit normally unstressed beats which are between the 2 strong beats. That doesn't mean you have to dance them all the time. You can then explore other things that most people don't do.