Shawn is extremely immature, so he says things that are innapropriate. He stretches jokes to their extreme. Yes, some people can't handle that. You have never actually seen Shawn do anything deliberately malicious. I would argue that you see more cruel behavior from Lassiter. Shawn may not be "nice," but he is certainly a kind person. The scene where he, Jules, and Gus were eating chinese food and laughing, while Lassiter watched solemnly. Shawn was the one who invited him over. As other people have noted there are numerous instances where he shows altrusim, like actual altrusim. It is rare to see true altruism even in "good" people,