Why is a sensationalized slideshow harmful to the presenter?

A presenter must always try to keep a formal, traditional and common style about the topic he is presenting to the audience, whatever these might be. Regardless of the intention of the presentation, a presenter should not include a sensationalist slideshow for two reasons:

First, it can caused a distraction from the presenter's main point of view or main idea.

Second, it can enrage the audience and make them want to leave the presentation.

In both scenarios the result is negative for the presenter.