I agree with most of what you say here, that beliefs control what you feel and do, that humans have an inherent instinct for empathy. However, evolution doesn't strive for improvement, it simply eliminates anyone who has traits that slightly decrease its chance of surviving. Empathy to a degree is advantageous for surviving, but if you actually sell everything you have and give it to the poor, that's going to decrease your chances of surviving.

So humans are not just one thing, whether greedy or empathic, they simply do what feels good. Emotions are a way how evolution controls the delicate balance that is just right on average for surviving. But other humans can exploit this: if you appeal to empathy, you can make them more empathatic, if you appeal to greed you make them less empathetic. Beliefs can make people focus on empathy more, or on greed and scapegoating. Belief is just the best model of the world we have right now, that if we admit it to ourselves we are subconsciously certain about that they are true. Consciously, we can make us aware of the fact that it's not actually certain, or that we just don't know, but we always have some "best model" of everything. Belief isn't inherently bad, people also belief that the earth is round, because it's based on scientific knowledge. We can consciously choose our beliefs, and those then heavily influence the way we feel, think and ultimately behave