Robin Hanson has some interesting thoughts about why people are so darned hypocritical:
"Food isn’t about Nutrition
Clothes aren’t about Comfort
Bedrooms aren’t about Sleep
Marriage isn’t about Romance
Talk isn’t about Info
Laughter isn’t about Jokes
Charity isn’t about Helping
Church isn’t about God
Art isn’t about Insight
Medicine isn’t about Health
Consulting isn’t about Advice
School isn’t about Learning
Research isn’t about Progress
Politics isn’t about Policy
“X is not about Y,” … mean[s] that while Y is the function commonly said to drive most X behavior, in fact some other function Z drives X … more. … Many are well aware of this but say we are better off pretending X is about Y..."
"I’ve argued that much of our behavior is poorly explained by the reasons we give, and better explained as ways to signal abilities, loyalties, etc. But if so, why do we act so astoundingly ignorant? Why don’t we know about, and explicitly acknowledge, these functions? Yes, it can look bad to brag, or to be consciously strategic about loyalties, and some observers may be usefully fooled by our idealistic stories. But are these really enough to explain our incredible ignorance?
Man the sly rule bender offers a more satisfying explanation: we evolved to overtly and consciously embrace social norms against bragging, dominance, and sub-band coalitions, while covertly and subconsciously signaling our abilities, and loyalties...
It looks bad to brag and to be consciously strategic about loyalties not just because those can in general look bad, but because they violate strong forager norms. We signal covertly and unconsciously because our ancestors were strongly punished for overt and conscious signals...
...the main reason we have huge brains is to hypocritically bend rules"
I'm still thinking about this (and I think Robin is too). It's certainly true that people have a tendency to ascribe loftier motivations to their own behavior than often seems to be the case, not only to others but also in their own minds. I'm not sure I buy the explanation here, though.