How is it different between "holding up the line" and "holding the line"?
Answer from a Native speaker
Great question. "Holding up the line" means that someone in a queue of people is doing something which is causing a delay to the other people waiting. They may be talking too much or taking a long time to pay, etc. In the case of the clip, he is arguing about not being served and that is what is causing delay to the other customers. "Hold the line" can have a few meanings depending on the context. First, if used while on the phone, it can mean to wait or not hang up while the person you're speaking to does something or gets someone else for you. Second, it can mean to stand firmly in a belief. To not change your mind about something regardless of pressure from others. Ex: I'm sorry to hold up the line, but I can't seem to find my credit card. Ex: Mr. Simpson is just away from his desk, can you hold the line or would you prefer to call back? Ex: Everyone expects me to back down but I will hold the line when it comes to gender equality.