Hah. People absolutely took them seriously and still do. They are pitched as if they're serious important art about issues. People discussed it like it was King Lear.
I mean, one actor took their role so seriously they locked themselves up in hotel room for a month in isolation to prepare for their role as Joker. Many people in film took it seriously.
Just because a piece is fictional or imaginative doesn't mean it can't be taken seriously
They're blockbuster movies about a comic book.