Agreed. I had this thought after I wrote the post you quoted. More on this below.
Two things: One being that every choice a parent makes for their child projects a set of values onto another; that other being their child. So I can't agree with you that such a thing, generally, is "almost always a bad idea". You and I, for example, had our parents' values projected onto us for a very long time, and have turned out to be relatively well-adjusted. (My affinity for Star Trek being a clear deviation from well-adjusted, but harmless nonetheless). Also, I would point out that as future physicians we will be very much in charge of evaluating the comfort of someone else's life when we decide how much and what kind of pain medication to deal out. Or whether we believe a patient is actually in pain at all or just exhibiting drug-seeking behavior.
The other thing is one of statistics. Projecting or not, we do have a cultural idea of beauty. Every culture does. I think most of us can agree that people who more closely fit that ideal of beauty (thin, symmetrical facial features, etc.) tend to be more financially successful in life. My point being that there is an argument to be made for cosmetic genetic manipulation from the perspective of the "betterment of the child". The obvious disclaimer being that financial success is not the only measure of success. Still, it is not a consideration to be lightly discarded.
I would point out, however, that the sentence in the movie after envirodoc's quotation states that the woman who had the "breeding, brains, and beauty" also "was incapable of love or tenderness or decency".
I would agree, hence my argument in my other post that these decisions be left, mostly, to the parents. We are already expecting them to make most of these "enforced-value decisions", e.g. circumcision, and we have reason to assume that these decisions will be made with care and for the betterment of the child. Hence my opposition to large scale societal control over genetic manipulation with regard to reproduction.