Actors aren't blindly going to work in a movie. They contemplate and decide if they like the storyline and plot. When the movie is going to highlight a societal issue, they would want to work on it to bring out the the supressed issues to the public eye. They would mostly first think of the advantages and disadvantages that are to arise when they get the opportunity to do the movie and then only work on it.
It seems fairly obvious that movies are a reflection of social norms. If viewers could not in some way recognize their own society in a film, it would be difficult to sympathize with the characters, or even to follow the plot. Movies that attempt to show a distorted view of social norms (for example, 1984, which is based on the book of the same name) can show us a warped reflection of current social norms and point out flaws in the way that we live.
Script writers are constantly adapting to the latest trends in society and including it inside their movie scripts, they do so because they know the public will identify more with the movie if they can relate to it, so I agree that movies are often a reflection of the current social norms in society.
If a movie makes references to sexual activity, for example, then there must be a demand for that kind of content. If a movie has lots of violence and fight scenes, then there must be a demand for that content as well. Moviemakers are profit-seekers who want to appeal to the current culture in order to develop a script that people can relate to.
While movies may use social norms as a plot device or in certain scenes, most movies eschew the complexity of social interaction in favor of interaction which breeds narrative rather than particular behavior. The average person is far less likely to engage in any activity that is shown in the movies than a Hollywood character is. Social norms may be reflected by film, but through a fun house mirror.
Movies are not a reflection of social norms and they should not be regarded as such. Movies present a lot stereotypes and they also inflate what would happen in real life. The purpose of this is to entertain because most peoples actual life stories are quite boring when translated to films.
No, movies are not a reflection of social norms, because they are the reflection of the world the way one person wants them to be. Movies are usually highly sexualized. People act in much more outrageous ways than they usually do in real life. Movies are the way the director wants reality to be, not how it is.