Watching movies indeed can be very infleuncial, because people tent to exhibit or mimic the the qualities of some of those characters in the movie.
The teacher is very correct in his teachings. Now, imagine a child watching action movies, shooting movies and fighting scene; you will see that after when he finishes watching the movie, he will want to perform those things he saw in a movie..
Now not only a child, even some grown up marriageable ladies, who are given to movies, watching those movies where the female characters cheats on their partners, and they feel that it's normal or later, they go back to their partners to apologise. Now this ladies failed to perceive or recognise that these things are done in movies, but they will stupidly want to mimic those characters by beginning to cheat on their partners who was supposed to marry them, and unfortunately the other gets to know what's going on, and their relationship which should have ended in marriage, failed. Why? Because of mimicking useless characters in movies. And they call them "role model".
The teacher speaks the truth. Instead of watching those things, why not even watch documentaries, or comedies or you study your bible or more you could read books on self-development. The Lord bless His teachings, Amen.