What is the difference between freedom of expression in movies versus community posts and comments?

‌If someone writes out an absurd and groundless conspiracy theory about leaders of the Democratic camp and uploads it to a large community bulletin board?
In that case, they would be taken to the "Democratic Police Station," wouldn't they?
But if it's turned into a movie, they say it's freedom of expression?
This isn't just my personal opinion; it's the view of all critics, regardless of whether they are from the ruling or opposition party.
Even Han Dong-hoon thinks this way—that we should view movies as movies.
So, is there some kind of law that says it's okay to turn the same conspiracy theory into a movie, but it's not okay to express it in writing?