'So questions about the "independent" effect of biological factors are based on a faulty premise. The sooner we stop asking them, the sooner we can focus on the important questions about how the complex interactions between biological factors and the environment shape various human characteristics.'
Well, you say those are the important questions. But it is surely right to insist on the specificity of the study of human biology as biology. The human organism offers up biological processes to study as such - like circulation, the lymphatic system, digestion and so on. So far the study of the 'how the complex interactions between biological factors and the environment shape various human characteristics' has been a pretty barren field by contrast.