Psychology vs Free Will

On May 23, Bob posted "Freedom, Truth, and Objectivity." In it he says, "This imaginary "Creator" supposedly endowed us with "liberty,"which is to say free will. But every leftist knows that we don't really have free will. Rather, we are victims of our environment and our genes. For example, poverty causes crime. Unless you happen to be rich. Then greed causes crime. Unless you haven't committed any crime. Then it's just a crime to be rich. But don't be confused--there's no objective right or wrong anyway."

Bob apparently believes in free will. But Bob is also a clinical psychologist. Isn't psychology supposed to be the scientific study of human mental processes and behavior? And isn't science supposed to be the systematic study of cause-and-effect relationships between phenomena? And doesn't this imply that psychologists, in principle, believe that human thoughts, emotions, and behaviors are phenomena that cause and are caused by other phenomena? And doesn't this mean that psychology, in principle, assumes that every thought, emotion, and act is caused by other phenomena, which, in turn, are caused by other phenomena stretching back indefinitely? And doesn't this mean that psychology, in principle, assumes that everything we think, feel, and do is determined by a constellation of interacting causal conditions that makes it anything but free to be other than what it is? And doesn't this mean that, in principle, a psychologist who believes in free will is oxymoronic?