It is very common for people of any background to seek out therapists and professionals who have a similar background (or maybe just the appearance of it). It comes back to the perception of the ability to relate and understand the unique issues of the individual. Suppose foot binding was still an accepted practice in the Chinese culture, a professional or therapist of a different cultural background would be reluctant to understand and/or accept such a practice. People do not want to be judged when they walk in for help and the most likely chance to avoid that is to find someone who will not judge is someone who looks like they would understand - even if those assumptions are based on very superficial characteristics.
Under what circumstances would you find a traditional Latino or a traditional Asian family in therapy?