Hi mike and welcome to DF.
But I do not agree. You also can also learn with seven or more instructors. No 1 shows you to stand upright, no 2 how to hold a woman, no 3 tells you the secrets of the music and its interpretation, no 4 takes you to your first milonga party and introduces you to the tango crowd, no 5 shows you to move elegant, no 6 may show you how to place your feet exactly, and no 7 will show you combinations and fancy steps. It took me 5 years to find a teacher that represented all said aspects.