Unintentionally funny

For most people the whole idea of demon possession is deeply disturbing. And it's presented in a realistic manner.
There is plenty of atmosphere. The words and actions of the possessed Regan were and still are shocking. There
were various reactions to the tension in the film, including nervous laughter. Although Blatty
and Friedkin attempted to attach religious significance to the story much of the popularity of
the film was due to the shock value.

I don't think it's 'an early seventies thing'. I've witnessed The Exorcist working its magic on people who weren't alive in the 1970s. The film has demonstrably stood the test of time.

It has never remotely worked for me. I think I too had a few chuckles at its expense when I first saw it. And when I was younger I was utterly baffled by its status as a classic. 'The best horror movie of all time'? Not even the best horror movie of 1973.

But I've long since come to understand just how subjective horror is. There are films I find disturbing (Blue Velvet, for example) that some of my friends think are utterly risible. Not every film will push everyone's buttons in the same way. Or at all. And when they don't, we might find them unintentionally funny instead.

The Exorcist is well-crafted. It almost entirely eschews jump scares. Lots of people do feel it has underlying suspense and atmosphere. And its slow-burn build-up is so effective (for those people it actually works on) that the film manages to scare them despite many of its practical effects looking decidedly ropey half a century on.

I think, however, what IMDBRefugee1SD says is interesting:

For most people the whole idea of demon possession is deeply disturbing.

No atmosphere? Are you joking? The Exorcist is one of the most atmospheric movies ever!

The Exorcist works better as a drama with horror elements than a horror film, true. If nothing else it's a much better film as the drama elements are top notch to anyone who can view the film from multiple characters' points of view.

I think today's more jaded responses to the film come form people being accustom to what they know today and reflecting back instead of keeping it within the frame of what it was when it was new. At the time The Exorcist was far beyond any other existing horror experience and straight out horror films were considered B grade at best. I can't imagine many horror films today with a solid dramatic basis.

I know a 27 year old who recently saw this movie for the first time. She were impressed, saying that it was better than many modern day horror movies ie. "The Conjuring." She did not call the movie "deeply disturbing," but it did inspire her to go buy and read the book immediately after.

I think the lack of music, establishing shots, tone, color scheme, setting, and acting all make this movie very good and not just a movie of its time. I too, hate when people say movies are good just because "fOr thE tImE it wuZ gUd." Give me a break. I would strongly disagree that The Exorcist falls into this category.