Women
I have a feeling, and this is just my humble opinion that humankind should be grateful mostly to women for the tango phenomenon. The men in Buenos Aires in those times had neither noble breeding, nor choreographic education. You can not expect the common sailors and workers to be fine gentlemen. But the women could form an attachment with a partner and stay with a man for the whole dance, whatever he did and however he moved. This is the source of such things as soft embrace, forward leaning pose, outstretched legs etc. All these attributes were not invented artificially. They appeared naturally, as tango is a true folk dance.
While learning tango it is very useful for women to put themselves into position of the women of those times, when men lined in a queue and fought for the right of dancing with a lady. The winner expected to receive a sweet dancing prize! This attitude would help women to gain quickly the authentic way of tango movement without losing time on imitations, which are extremely hard to unlearn.