You misunderstand the word "editing" in this case. It's not a matter of adding a few plugins and cutting audio. It's a matter of having the tools to normalize human voice in a way that it's expected in a movie, or to have automation about it, or envelopes that tracks the volume and fixes it for you. That's the stuff that neither audacity nor kdenlive has, because they're very specific to the movie industry. They have more generic plugins instead.