Powerful, generally undetected euphemistic processes in language give us a falsely optimistic model of the world.
The Origin of Euphemistic Distortions
The formation and use of euphemism is a powerful, inevitable process in human language. Every day, subjects must be discussed or alluded to that could cause discomfort in the parties to the conversation, detracting from both the informative purpose of the conversation and the (generally more important) social bonding function. To avoid the discomfort, taboo subjects are discussed in a circuitous manner, removed as much as possible from the disturbing aspect of the topic. Disturbing aspects are ignored, reframed, treated symbolically, or otherwise elided.
On the level of diction, words and phrases are found to bring to mind the relevant aspects of a topic, while minimizing the disturbing or irrelevant aspects. Metaphor and metonymy are common mechanisms for euphemism, but there are many such methods, with not just new euphemisms, but new euphemistic mechanisms, being invented all the time.
But euphemism does not only happen on the level of word choice. From micro- to macro-, from the foundational narrative/legend of a society to the way social relationships are cognized, human language users and language-using communities and even nature (via evolution) are acting on language to orient human thought in euphemistic directions. How our brains conceive of the world (including language) is not related to what's actually important in a universal sense, but to what was important to organisms' fitness goals in the environment of evolutionary adaptedness. We do not perceive all wavelengths of light or sound, but only those that (a) were relevant to survival in the EEA and (b) for which a perceptive apparatus was evolutionarily available. (And we do not perceive things like X-rays at all.) Similarly, language does not give us a picture of what is, but only a picture of what was relevant to survival in the EEA.
Artists Explode Euphemism
The project of artists (and of phenomenology) is often to explode euphemistic ways of thinking. In "Dulce et Decorum est," Wilfred Owen does so for the romantic idea of glorious death in combat. Patriotism and a euphemized conception of those fighting may be more comfortable and politically expedient for the folks back home, but here's how it really is, says Owen, here is what is elided: the boy who doesn't get his gas mask on in time, "guttering, choking, drowning," "the white eyes writhing in his...hanging face, like a devil's sick of sin," at every jolt of the wagon they "flung him in," the "blood/come gargling from his froth-corrupted lungs." Happy Memorial Day.
What does this tell us about the accuracy of the model of the world we have from language? Is our conception accurate? Too rosy? Too negative?
We might expect our visual picture of the world to be "too rosy" if we found that our instrument for detecting red light (eyes, brain) were set too high compared to the mechanism for detecting other kinds of light. Analogously, an understanding of the linguistic phenomenon of euphemism might lead us to suspect that our conception of the world may be too optimistic - unless, of course, there were a countervailing, dysphemistic process. However, a moment's reflection shows us that the effect of any dysphemistic process is only a tiny fraction of that of euphemism, at best.
A main function of euphemism is to avoid social discomfort. The idea of suffering is always socially uncomfortable - we should expect it to be edited out. There is rarely any reason to add pain (or social awkwardness) to already-comfortable language - this is the task of the artist and the philosopher alone.
The Mistaken Notion of Pure Language
Less subtle thinkers than Wilfred Owen have hoped for a world of clean language, without euphemism. This is a mistaken hope.
All language has connotation as well as denotation - an emotional message as well as an informative one, even if that emotional message is one of blank neutrality. We do not think without emotion; in a practical sense, we are incapable of doing so. Without the swift functioning of our emotions, we are crippled at such "simple" cognitive tasks as making decisions (see, e.g., "The role of emotion in decision-making: Evidence from neurological patients with orbitofrontal damage," by Antoine Bechara, Brain and Cognition 55 (2004) 30–40). Why should language not take advantage of this fast system of cognition whose output is chemicals?
Language "cleaned of its emotional message" is not purer or realer or truer language - it is systematically distorted language. Making a project of eradicating euphemism immediately begs the question of the objectively correct word or conception for a given thing or act. "Crack baby" or "drug-exposed infant"? "Crack baby" one might call politically incorrect, vernacular, plainspoken, suggesting that "drug-exposed infant" is the euphemism. The latter, though, is the term used by child welfare professionals (nurses, social workers) to indicate that a horrible violation happened to this innocent infant child, emphasizing the wrong done to the child. Can you hear the screams more from "crack baby" or "drug-exposed infant"? See the tubes and the shaking and the tiny hands? And which better expresses that the mother of said infant used drugs to ease her pain from having been viciously sexually abused during her childhood?
All words are euphemisms. All language is euphemism - selection of relevant, comfortable aspects, and elision of pangs of empathetic pain so far as possible.
"Rape" is a euphemism. "Prison" is a euphemism. Even "prison rape" is a euphemism. Words indicate concepts, but cannot ever express how bad these experiences are for those who suffer them.