As transitional devices, they carry a story forward. Both Associated Press and United Press International style guides acknowledge circumstances in which editing a quote is not just appropriate but recommended. In fact, UPI strongly advises writers to remember the difference between spoken and printed language. News writing isn't a transcript of reality. It's a creative and analytical enterprise fueled by the exercise of selective judgment.
Quotes are, in fact, an artifice.
Even literally rendered, they take on certain implications, depending on the context of the article. Journalists need to get over the idea that they're models of ethical probity and beacons of objectivity if they never touch a quote. But a major newspaper did it. Direct quotes have clarity and force on the page out of realistic proportion to the spontaneous rush or sputter of the spoken word. Nobody's arguing for homogenizing colorful vocabulary that gives readers a sense of someone's personality.