..."it assumes that the viewer either recognizes the song and knows the meaning of the lyrics, or understands French well enough to translate "Non, je ne regrette rien."

Not necessarily. The people who put ads together may sometimes be creeps, but even so they are also competitive and often enough creative. Selling things to the public isn't necessarily the main point. They are probably more motivated a lot of the time by the hope of impressing their peers, and winning awards.