After the 2004 iowa caucuses, the press repeatedly showed an unusually awkward clip of howard dean screaming rather than any substantive portions of the event. what does this illustrate?

This illustrates a soundbite

Soundbites are when the media takes only a small part of a video or an audio clip and uses it as an example and a reference point for the original thing. The idea of it is to capture the essence of the problem, and in this case, the famous clip of what was titled as the scream was supposed to exemplify everything regarding that person.