Precisely. I think the author is saying a talk should have a thesis statement that is novel. That is true. But to convince the audience of the thesis statement

Precisely. I think the author is saying a talk should have a thesis statement that is novel. That is true. But to convince the audience of the thesis statement, the speaker needs to cite evidence. The evidence cannot be surprising. Since most of the talk needs to be evidence, and therefore not surprising, it’s foolhardy to eliminate all that is not surprising.