As someone with an education in the subject, I can offer a little insight here. Psychology, just like other sciences, has always been at odds with the religious right. And yes, it is a science. We use the scientific method to gather data. However, it's often referred to as a "soft science" due to the lack of certainty when it comes to interpretation of the results of research, coupled with the fact that humans are incredibly complex.
The religious right often don't believe in mental disease, ignoring experts on the subject. They think that depression can be cured with prayer or just realizing how good they've got it. They don't believe in alcoholism as a disease, and think that it's just a problem of behavior. They are ignorant or dismissive of the nature vs nurture debate, instead perpetuating the myth of free will, and using their belief as an excuse to condemn people who make bad choices. Although some churches are finally coming around, the church has traditionally used pastoral care as a substitute for professional psychological help.