Not. A police officer when making an arrest does not want anybody behind him, in that close of proximity to him. Ask any one.
You are correct about the close proximity and behind. However, I am friends with many LEO’s. I haven’t heard one yet say this guy was right. All said that he was within his rights to ask her to move - back but most of my friends felt that was even a power play. The officer was turned toward the lady taking the video most of the time.