It seems like so many movies these days have some random ass person in the cast who doesn't belong. Examples:
-Vince Vaughn in Hacksaw Ridge
-Louis C.K. in Trumbo
-Kristen Wiig in The Martian
-Tyler Perry in Gone Girl
-Seth Rogen in Steve Jobs
And now Harry Styles in Dunkirk. Did anyone notice this?
It doesn't mean they don't "belong". A lot of actors come from music performance background, or standup, or other entertainment professions.
- Jim Carrey, comedian
- Chris Rock, comedian
- Mark Wahlberg, rapper
- Frank Sinatra, singer (From Here to Eternity - won an Oscar for best supporting actor)
- Johnny Depp, rock musician
- Cillian Murphy, rock musician
You're not the first to voice this let alone point it out. I don't know Harry Styles nor ever heard of him so I don't care.
What's missing in movies is same as in society: a good sense of work ethic and living up to ideals.