A second factor is the journalistic culture of the news conference, which rewards zinger questions that provoke news--and discourages anything that courts televised dullness.
People only want to watch exciting news so conferences have to be exciting. 
mnli hypothesis: People only want to watch exciting news so conferences have to be exciting.  premise: A second factor is the journalistic culture of the news conference, which rewards zinger questions that provoke news--and discourages anything that courts televised dullness.