This may not make you feel better but here goes. An admissions officer at an Ivy League school once said that for every non-qualified candidate they must admit (son or daughter of wealthy alumni, or maybe legacy) - if the admission rate was 12%, they would have to reject 8 otherwise qualified applicants.
In the case of Caltech, they may have looked at your major and decided that they wanted less Foo majors and more Bar majors. All about recruitment. Either way, I'm sure someone argued your case, as brandnewlow commented.[1]
I get the point you're trying to make but that's not exactly true. For every legacy candidate they admit, they must reject exactly 1 qualified candidate as a result.
For every candidate they accept in general, they must reject 8 others.
In the case of Caltech, they may have looked at your major and decided that they wanted less Foo majors and more Bar majors. All about recruitment. Either way, I'm sure someone argued your case, as brandnewlow commented.[1]
[1] http://news.ycombinator.com/item?id=521107