Could rhetorical have a positive or negative effect on an audience?

Rhetoric can have both a negative and positive affect on the audience depending on the subject being discussed and the education level of the audience. For example I would never go into to a long rhetorical dissertation about creationism to an audience of teens and children or people who have no clue about creationism. It can be positive if it is used to stretch the think and logical reasoning of the audience, such as in a classroom or lecture room. The idea of rhetoric is not to confuse but to introduce a point and come to a conclusion. If you confuse your audience you have cause a negative effect of confusion of the listener.