Klout generates your most influential topics based, not just on what you talk about the most, but what you are most influential about. You can remove topics you don't think fit your social presence by clicking the "x" on the right hand side of the topic when you hover over it. You must be viewing your full topics list or the "x" will not appear. Then the topic will be hidden from public view.
You can also add topics to your profile that you think are more relevant. Learn more about adding topics here.