We Are Everywhere - Instead of New York being mostly assassins, I would argue this scene is more Winston getting a very large group of assassins together if the meeting with Wick turns bad. He had 4 accompany him to kill Perkins in the first film, and he would know and fear Wick's killing ability, so he filled the fountain area with backup and reveals his hand of "I was prepared" after they come to an agreement and he doesn't think he'll need to kill Wick after all.
We Are Everywhere - Instead of New York being mostly assassins, I would argue this scene is more Winston getting a very large group of assassins together if the meeting with Wick turns bad. He had 4 accompany him to kill Perkins in the first film, and he would know and fear Wick's killing ability, so he filled the fountain area with backup and reveals his hand of "I was prepared" after they come to an agreement and he doesn't think he'll need to kill Wick after all.