A recent blog post by Darcia Narvaez is an interesting example of how people can confuse what they want to be with what is. She paints a pretty picture of the way she would like the world to be and, as a result, humans must have been that way and it's only the modern western world that has corrupted us so...we just need to get back to our natural selves that lived in a peaceful garden of eden. But there is a problem here. There is no evidence that humans lived that way. Clearly there was cooperation within groups (based on anthropological data and accounts of the last surviving groups of hunter gatherers), but anthropological data and the fossil record also suggests a non-trivial amount of violence (evidence of broken bones, cracked skulls etc). No one knows exactly what the level of violence was, though a variety of inferences have been made based on the available evidence.
Narvaez also states that evolutionary psychologists have forgotten that much of our history as a species was spent living in hunter gatherer bands. In fact, I distinctly remember being taught exactly that when I was an undergraduate taking evolutionary psychology. I remember hearing and reading about the !Kung and the Yanomamo among others and the different social systems that humans have had over our recorded history. She accuses EP'ers of "transposing our social environment" to the past. On the contrary, many of us, myself included, study how the mismatch between the past environment and the current one can cause us grief by causing our adaptations to produce maladaptive behavior (Psychopathology or Adaptation? Genetic and Evolutionary Perspectives) while others focus on how adaptations that evolved in the past function well in the modern world. While some aspects of our environment have changed (technology, big cities, etc.), we are still a social species that reproduces through sexual means. Not everything has changed.
She states "There was deep collectivism and group identity. No one wanted to be alone. Yet EP assumes detached, territorial, possession-driven individuals much like us today." I have yet to read any EP derived research that does not recognize the role of the group. As a social species, being ostracized from one's social group, over much of our history, would have meant death. In fact, there are a number of EP studies that look at the role of group identity and ethnocentrism and how this plays out in terms of the current dynamics that we see happening around us, not always in a positive way.
"Children had the freedom to roam and do what they wanted, like adults." And this is based on what exactly? Scientology? Children are not just small adults and I see no evidence provided that suggests that they were treated that way in the past. When small, they needed parental care and protection. Roaming around within the confines of a tribal area surrounded by kin is one thing, doing whatever they please seems somewhat different. While one's parents and other relatives may be highly invested in a child's welfare, it's unlikely that nearby predators are going to be interested in anything but the tasty dinner-sized hairless ape sitting on the ground. While modern society takes overprotection of children to the extreme (Free Range Kids makes some good points about this issue), suggesting that children had the same freedoms as adults ancestrally isn't a good argument for it. Especially when the anthropological literature abounds with examples of parents dictating (or directing/influencing with best interests at heart, depending on your perspective) the mating/marriage choices of their offspring. EP does not globally assume the nuclear family in the past, in fact a great deal of scholarship focuses on alloparenting, the role of grandparents, helpers-at-the-nest, and the role of fictive kin. Of course, much attention has been paid to mothers in particular (see Sarah Hrdy's Mother Nature: Maternal instincts and how they shape the human species) with regard to parental investment as they do provide the bulk of early care cross-culturally and ancestrally.
"There was virtue and good citizenship, a natural morality, yet EP assumes that humans are natural cheaters." Actually, many, but not all, EP'ers see evidence that humans are natural cheaters and cooperators based on numerous studies (for cheater detection studies see Tooby and Cosmides, morality see Krebs, reciprocal altruism see Trivers, psychopathy as life history strategy see Lalumiere). Cheaters prosper when they are rare and hard to detect or when they cheat just a little or even when they provide a valuable service in other areas so you can put up with their annoying behavior in this one instance (like a partner who's a great lover, good cook, has a good job but refuses to clean up around the house...the good may outweigh the bad). Of course, cheaters may be more common now because it's easier to get away with in it large mobile societies as reputation is less powerful and easily passed on than in smaller groups. There's a great discussion of this in Amy Alkon's recent book, I See Rude People.
Seriously, whenever someone makes statements about what evolutionary psychologists do or do not claim, I suggest picking up some EP research to read for yourself.