Sorry, nothing can be done on any plane without the Captain's approval. Captain is the final authority, this purser Jose can't remove a fly from the aircraft without the pilot in command,s approval.
Exactly. I agree with you that this should not be the way things work, but unfortunately it is (look at almost any story that people got taken off the plane).
Purser walks into cabin and says "Captain, remove 2 people from the plane". Captain says "Sir yes sir".
Passengers get taken off, plane takes off.
The captain is not a customer service / deescalation rep.