Making pro-gun activists look foolish

Jeva Lange has an article in The Week about some manipulation of the news:

The makers of a new Katie Couric documentary on gun violence apparently deceptively edited an interview with gun rights activists to make them appear stumped by her question, The Washington Free Beacon reports. About twenty minutes into the documentary Under the Gun, Couric asks members of the Virginia Citizens Defense League: "If there are no background checks for gun purchasers, how do you prevent felons or terrorists from purchasing a gun?"
The response? Dead silence, for about nine awkward seconds:

That's not how it really went down, though, according to activists who contacted the Free Beacon. In audio provided to the website, Couric's question is actually quickly met with answers, and the back and forth lasts about four minutes:

The gun rights activists have called the segment "unbelievable and extremely unprofessional", as "Couric intentionally removed their answers and spliced in nine seconds of some prior video of our members sitting quietly and not responding. Viewers are left with the misunderstanding that the members had no answer to her question," Virginia Citizens Defense League president Philip Van Cleave said.
When asked about the edits, Nora Ryan, the chief of staff for EPIX, which is airing the documentary, said that the channel "stands behind Katie Couric, director Stephanie Soechtig, and their creative and editorial judgement."

Rico says that, given the leftward bias of news people in general, why are you surprised?