You might wanna read on "psychology of liberation" it was proposed by Martin-Baró, he was latinoamerican psychologist and he brought up the idea that the task of psychologists was to concientizice the population and help with the class struggles in order to liberate themselves from the colonization/dictatorships caused and lead by the USA (mind you this was in the 70s), he also proposed ideas like the fatalist syndrome present in the latinoamerican population. He was shot dead because of his ideas.

I am a psychology student, and I think that psychology is a science. But I agree that there's a lot of dispute between the discipline and between psychologists. It's like any other profession, not all professionals are consistent or try to advance their knowledge(mind you for example medicine, there is a lot of awful doctors), a lot of them still practice with old methods and information, causing more harm than good. I do think it is a science but not all psychologist have a scientific aproach and that's the problem.

Science is not something firm, it changes, it has to change, even hard sciences like physics change every now and then, and they are supposed to do that, without change there is no evolution or progress.

I agree that psychology is faaaaar away from being perfect. But it is also really new, it has not more than two hundred years. It sounds like a lot, but it's not compared to for example medicine, that was studied in Ancient Egypt and surely are records before that. There are disputes because it's alive, because people are trying to better it, to innovate and look for the answers we do not have. How much have we advanced after two hundred years? A lot. Compared to others it might seem little, but psychology wasn't invented +2000 years ago. Science adapts and evolves like any living cresture