I don't have a problem with this, since he was just joking around. I think there are other things about Giuliani that are more worth worrying about than a comedy bit he did with Donald Trump. I can't see how anyone can seriously gain any information about his leadership abilities from this clip.
Be honest, if this were Biden would you use this against him? Also it's not like this is a one time thing. He's done this before. Once is weird. More than once is a habit.