This makes some interesting points, but it is a bit of a misrepresentation of a few things. Psychology as it refers to the inner world of a person is a fact of existence and so exists with or without religion. In fact, you could make a cleaner argument that religion is a product of psychology. When you talk about the field, sure that can be argued, but it really only seeks to study this thing we all possess, and the approaches there can be criticized for sure, but to toss it all out is reductive. Modern Psychiatry (post-1950 or so) as a field is certainly something that is worthy of criticism, particularly around the DSM and drugs axis, but this doesn't make psychology less valid as a field or fact, and maybe depth psychology in particular. If you really want to make a case for something that replaced religion, the better target would be modern political ideology (since 20th century). The original sin and other comparisons fit far better there.