Might have something to do with the fact that happy/sad is neither an accurate nor an encompassing description of the uses of major/minor chords, unless you place a C major and a C or A minor directly next to each other. I for one find that when I try to tell the difference solely on that basis, I might as well flip a coin and my success rate would go down only slightly. When I come at it from other directions and ignore the emotive impact, my success rate is much higher.
In short: Your conclusion doesn't follow from the evidence.
I stated the evidence incorrectly, look at the uncle/aunt of your comment (if you haven't already) for the actual evidence.
Here's the new thread for posting quotes, with the usual rules: