I'm sorry if it's a silly question to ask.
Is the definite article required or is it optional in:
1. I love Harry Potter movies/films.
2. I love the Harry Potter movies/films.
I think #1 should be used when referring to Harry Potter movies/films in general. #2 sounds as if the speaker loves the movies/films that has been previously mentioned in a discussion - he loves a few of them, but not necessarily all of them.
Do I understand it correctly?
Both can be used.
1 means "I love any film with Harry Potter in".
2 means "I love the series of films with Harry Potter in".
I was trying to think what I might say about James Bond films and I might use any of:
I love James Bond films.
I love a James Bond film.
I love the James Bond films.
The second would probably be used in conjunction with something like "on a wet Saturday afternoon".
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.