Because the governmental bodies and mortgage associations never thought to do any analysis? They just went on blind raw data because they are all too stupid and unscientifically versed to look into the nuances? Is that really your position? Really?
I linked you an entire story that was nothing but analysis (The History of Lending Discrimination) and then quoted to you extensively from it, including references to various other studies done at major universities (where they apparently don't bother with scientific rigor either?). Go back and reread.
You are deep, deep in cognitive dissonance land, dude.