A critique of segregation/racism?

I'm not positive, but I believe I detected in this movie an oblique criticism of American racism. Of course, simple realism demanded that the menial laborers-- baggage handlers, cooks and servants-- be black, but it seemed to me that the shots including them made them rather conspicuous, so that we can't help but notice all the drudge-work is done by black people. And of course there is the bit of comedy early on involving the baggage handlers finally tricking Taylor and his associate into taking Smith's luggage (including the pigeon cage)and running off. Granted, that could be taken as a dig at the lazy and duplicitous baggage handlers, but Taylor and his company were not presented in a very positive light to begin with, and I think even in 1939 the audience might not have thought it very kind of them to saddle the baggage handlers with heavy luggage indefinitely while they looked for Smith. Couple this with the brief but striking shot of the elderly black man looking reverently up at the statue of Lincoln, and a theme may be detected. The reality of legal segregation and a general inferior position for blacks contrasts sharply with the democratic, egalitarian ideals Smith is smitten with. Again, I'm not sure about this, but I think on some level Capra (who produced the wartime film "Negro Soldier," highlighting the contributions of black soldiers) meant his audience to contrast the stirring demand for justice that Smith was making on the Senate floor with fact that segregation and a generally inferior position was the reality for blacks in America (indeed, in Washington D.C.). It's subtle, but I believe it is there.