Bel Powley in The Diary of a Teenage Girl (Sam Emerson/Sony Pictures Classics)

According to Autism Daily Newscast, The Diary of a Teenage Girl is an “awkward movie to sit through.” Gee, what could feel awkward? Was it the shots of hot, moaning sex between a 15-year-old and her mother’s grown-up boyfriend? The threesome the two of them have with her best buddy? The 15-year-old blithely dabbling in prostitution, or the scene where her gal-pal pimps her out to score drugs? Awkward? What are you, uptight?

Thank God for Autism Daily Newscast. I seized on the site’s welcome denunciation while wondering if I had become a hopelessly out-of-it old fuddy-duddy. Apparently my transformation to moralizing bore is complete. Everyone else seems to think Diary is “nonjudgmental,” “vibrant,” and somehow fabulous because a teenage girl is “owning” her sexuality. So I guess it’s me and the autistics against the world.

The film is adapted from Phoebe Gloeckner’s novel of the same name, which takes place in 1970’s San Francisco. Patty Hearst is on the news, hippies are turning into punks, and horny, bored Minnie (Bel Powley) is desperate to get laid. Luckily Mom’s wimpy but manipulative beau, Monroe (Alexander Skarsgard), is on hand to oblige. They conduct a steamy rut-fest behind Mom’s back— it helps that Charlotte (a one-note Kristin Wiig) is frequently stoned or drunk out of her gourd. She’s also a narcissist who sexually competes with her daughter, livening up the breakfast table with encouraging remarks like “I was quite a piece when I was your age.”

So you go, Minnie. Stick it to Mom. As with most emotional aspects of its story, Diary leaves the underlying motives for this charged act of betrayal unexplored. Minnie records her adventures on cassette tapes (a bad idea, as it turns out), and animated drawings from her notebooks come to life on screen to reflect her state of mind as her coming-of-age exploits get wilder and wilder.

Perhaps today’s helicopter parenting and social media outrage have created nostalgia for a looser, more freewheeling past. Not for me. I shook my head when Monroe proudly showed off his erection to Minnie in a bar, I winced when Minnie gave a boy head for 15 bucks, and I turned my face away out when Minnie and Monroe took LSD together and he screamed and howled through a bad trip. Diary rubs our faces in increasingly sordid (and redundant) situations, but coyly holds back from confronting what they really mean.

Minnie’s walk on the wild side could be more compelling if something stood out about her. But nothing really does. Minnie, as acted by Powley, is a bit of a blank, and her observations are not unique. (“I had sex today. Holy shit!”) Her reaction to the craziness and dysfunction swirling around her seems flat and shallow until the end, when the madness becomes too much even for her and her defenses finally break down. We are supposed to admire her art, although all it is comic book, Robert Crumb-style kooks with gonky eyes and bodacious hard-ons. We’ve seen a lot of this sort of thing for years.

Diary throws many ugly scenes at us and then ties them all up as neatly as an after-school special, with the bland affirmation that Minnie is older and wiser because of what she’s been through and that she’s destined for great things. Sorry, not buying any of it, and sorry, too, that this movie has turned me into Mike Huckabee, only thinner.