It's natural that scholars will try to understand the world with the tools they are familiar with, just as a surgeon might be more likely to think of a surgical solution to a medical problem. The problem is when your tools have an implicit theory embedded in them.
Ever heard of the nature-nurture debate? The debate is over whether behavior is caused by a genetic/biological factor or a cultural/learning factor. It's ages old, predating psychology. Philosophers once split themselves into empiricists (nurture) and rationalists (nature). In artificial intelligence there is an analogous debate regarding symbolic knowledge (nature) and probabilistic and numeric learning (nurture). There's a good reason this debate is important-- for many behaviors, there are genetic and cultural factors.
Cognitive science tries to understand intelligent systems, and the nature/nurture debate rages in it. This is very fortunate. We end up with useful findings, such as that 60% of your happiness is due to a predisposition, and the other 40% are based on your environment. See The How of Happiness.
Unfortunately, (cultural) anthropology and sociology do not have means to study genetic predispositions in their methodological toolbox. As a result, predictably, they tend to be very dismissive of "nature" explanations. They seem to have a knee-jerk reaction against them. This is a shame. At its worst, they end accusing scientists of being sexist, stupid, or racist.
Here is how I believe it works: an anthropologist, say, becomes an expert in studying culture. She thinks in terms of culture. She sees its vast effects. She is familiar with cultural explanations of why things are. This triggers the availability heuristic, which is that we tend to think things that are easily brought to memory to be more probable, common, and plausible. Genetic explanations suffer from this heuristic, and the anthropologist has (unconscious) factors making them seem useless. In addition, their lack of understanding of genetics and and the methods used to study them make them unqualified to even judge their quality, just as I'm not qualified to dismiss a physics theory based on what I know of cognitive science.
There are other factors at work here, of course: anthropologists tend to be liberal, and equality is a strong liberal value. Anthropologists (as with others in the humanities and social sciences) might be reacting against the harder sciences because they feel marginalized by them. They might resent how quickly the media picks up, distributes, and overstates genetic findings.
None of these are reasonable excuses, however.
The research on the genetic component to behavior is strong enough that outright dismissal of the resultant theories is unacceptable. It is particularly troubling because there are many instances of behavior triggering genetic expression (that is, some genes will start working (making proteins) when triggered by some environmental stimulus.) A great example of this is stress.
See also the book The Agile Gene. If a whole field of science is on the nurture side, these fascinating, important, and subtle ways of our world will remain undiscovered, at least by that field.
The debate will continue its healthy rage in cognitive science. Anthropology and sociology should have their own nature/nurture debate, rather than dogmatically always being on one side of it.
PS: I love anthropology; I cite it and have done anthropological and ethnographic work. I am only quibbling with this one aspect of it.