Not sure why others seem to disagree, but kow-tow indeed conjures up fu manchu-esque images, a sort of comical or repugnant representation of groveling associated exclusively with Asian culture. Exactly as you say, it's not necessarily racist in intention of using the term as subservience, but racial nonetheless. Separately, the actual kau-tau seems to have meant something specific as a ritual of respect. Used here, its generalization to mean forced groveling or appeasement is strange, as it implies the person or entity doing it is a loser.