That could very well have been a "biased stop." I don't know that I've ever contended that there aren't instances of "bias." The argument from folks with whom you align is that such things are "systemic." What follows is some convoluted, extravagant conspiracy theory.
Cops are prone to making calculations like we all do. Black-American males commit a disproportionate amount of crime. Few would argue with a cop paying more attention to a male than a female in a similar situation based upon the fact that males commit crimes at a wildly disproportionate rate compared to females. Does that mean that cops hate men?