In our society (as in most) we cover our genitals (& female breasts) with clothes, and usually talk and act as if they did not exist. At some level we know they exist, that they may be sexually aroused, and that if exposed others might better see our arousal and become aroused or disgusted. But it is usually considered extremely rude to expose one’s or another’s genitals, or to explicitly discuss their arousal.
Folks who violate such norms usually send bad signals, e.g., of their lack of awareness of social norms, their lack of self-control, and their low opinion of the sexually selectivity of others. If a small child were to expose their or another’s genitals, the social norm is to quickly get them to stop, perhaps make a quick smirk or joke, and then change the subject. It is not so much that we don’t know we all know that genitals exist, can be aroused, or can induce arousal, as that we know pursing the subject looks bad.
This seems to me a helpful metaphor for understanding how people react to factoids that expose our hypocrisies. Consider common reactions to hearing that:
medicine has little correlation with health
few show much interest in medicine quality
police internal affairs report to police chiefs
college graduates rarely use what they learn
moral philosophers are not more moral
managed funds on average lose money
few give much to foreign or future poor
voters dislike politicians committed to promises
Most folks either grab at flimsy excuses to deny or excuse such things, or express mild polite interest and then change the subject. They don’t want to act like the subject bothers them, but they also don’t want to pursue it. Only oddballs excitedly plan how to fix such things, or analyze the exposed hypocrisies without making clear they don’t apply to present company. Socially savvy folks know that exposed hypocrisies, like exposed genitals, are usually best ignored.