Talking on the phone during a movie is disruptive to other people and hence it is not polite but rather inconsiderate and typically people don't like noise or distraction.
Consider the statement "I really don't like it when people talk on the phone when at the movies.". Based on this "I think it's really polite when people talk on the phone during a movie and disrupt everyone's experience" a true statement? Yes, no, or I don't know?