No, I think a tendency towards racism is an inbuilt trait (or consequence of inbuilt traits) in most of humanity. Humans will then seize upon whatever is handy (sometimes religion, sometimes science) to justify their inherent bias.
"For example, if you believed whites were inferior because they tended to have a higher percentage of body fat. Or that blacks were inferior because their average brain mass was smaller. Or that Asians were the preferred race because their average IQ is higher.
If that were the case, would it or would it not make sense to encourage the reproduction of races with preferred traits, and to discourage the reproduction of races with bad traits?
You are seriously misinterpreting an important part of basic evolutionary theory. There is exactly one criteria of a 'good' trait in evolutionary theory: a trait that increases the frequency of successful gene transmission is 'good'. That's it. Stupidity, body fat, and math ability have absolutely zero to do with evolutionary 'goodness' unless they impact reproductive success (and are heritable characteristics). So it is impossible to draw justification for any breeding program whatsoever from evolution itself; evolution is value-neutral.
"Additionally, what about people with genetic defects? I use quotes because there is a variety of opinion as to what genetic defects are. For example, if you are committed to an evolutionary world view, does it make sense to allow people with diabetes to reproduce? How about people with cerebral palsy?"
Like I said above, from the perspective of evolution, there is only one kind of 'genetic defect': one that prevents you from having kids (or prevents your relatives from having them). That's it. An example: Matthias Buchinger, who was basically a flipper baby. Genetic defect, right? WRONG. This little guy had fourteen kids, which makes him a smashing evolutionary success. Certainly more of a success than me, with my strong healthy limbs and paltry brood of children.
Finally, I have a question for you. Do you disapprove of eugenics because you think it is immoral or because you think it doesn't work? The examples you cited for eugenic improvements would certainly fall under the umbrella of so-called 'micro-evolution', which virtually every creationist accepts. So if you accept micro-evolution, wouldn't that make you just as inclined towards eugenic tinkering as the highest high priest of the Church of Darwin?
“Do you disapprove of eugenics because you think it is immoral or because you think it doesn’t work?”
Both, because I think anything that is immoral ultimately does not work.
“There is exactly one criteria of a ‘good’ trait in evolutionary theory: a trait that increases the frequency of successful gene transmission is ‘good’.”
I have not studied evolutionary theory exhaustively. It was taught to me and believed by me until I reached adulthood. That said, I thought a ‘good’ trait would be one that would enhance the survivability of a species. Diabetes, cerebral palsy, etc., do not. That is why I called them “undesireable traits.”
It is true, breeding against certain racial traits or breeding with a eugenic mindset is in fact “micro-evolution,” in other words, it’s contained within our species. So I see your point there. Those of us who believe we were directly created could still get into eugenics and such and not embrace evolutionary theory.
I think if you really believe that everyone in our species is equal before God, equally valuable, whether “defective” in some way or not, you’d be less inclined to be of a racist or eugenic mindset.
Similarly, if you believe we are the product of billions of random mutations with billions of random mutations in our future, with only the strong surviving, you might take a dimmer view of anyone who is handicapped or who you perceive to be inferior.
I don’t know that this would convince anyone to give up being evolutionary in their thinking. But I do think we need to consider the ramifications of our view of things.