Sherry Swanson (Maggie Gyllenhaal) is a mess.

Recently paroled after three years in jail, the none-too-bright girl with the trash Jersey wardrobe and the penchant for snorting smack is taking things one step at a time when “Sherrybaby” introduces her. She’s going to recovery meetings, being a good girl in the halfway house where she’s got a room, trying to get a job, making her meetings, going through the appropriate channels to visit her brother and sister-in-law’s suburban home, where they’ve been raising her young daughter in her absence.

It’s amazing how easy it is to hate Sherry, to sneer at her cheap polyester working girl suit and the gold cross she wears every day. It’s easy to loathe her, on behalf of the family who picks her up off the front porch where she crashes, on behalf of the little girl who doesn’t know whether to call her Mom or Sherry, on behalf of every

random person who comes in contact with her drunk rages and crying breakdowns. It’s stunning how easy it is to shake your head at how she can’t help but welcome the indiscriminate sex acts, can’t resist being unhinged by alcohol, can’t stop taking every bad situation and turning it into a way to self destruct, lower and lower.

Of course, there couldn’t be more foreshadowing if the screenplay had been written by Will Shakespeare. Things go from bad to worse to imminent destruction in almost horror movie “Don’t walk through that doorway!” style. But it’s like screaming at someone limping along in a marathon, and then realizing that her legs are broken.

There’s a twist - the audience gets a glimpse of why she is the way she is. And ultimately, there’s a semi-tidy happy ending to the movie, but the ending doesn’t really matter (in the world of drug addicts, as in cinema, oftentimes those around a disaster type like Sherry just cling to any scrap of hope that things will get better). Sherry Swanson’s story grates on you, and it’s easy not think about why.

Why is this movie so annoying? And why does that make it succeed?

Because Sherry is an anomaly all too common in America. It’s not that she dove into drugs with the abandon of a bridge-leaper. It’s the why. It’s not her shredded psychology. It’s the fact that, barring a deux ex machina, she will never receive adequate care, nor know that’s what she needs. It’s not her addiction. It’s the fact that that, and indeed she, is a symptom of a larger, cultural disease that it is in no one’s political or business interests to treat.

If she is an infant, as the movie’s title states, then what sense does it make locking her up for a tantrum instead of treating the root cause? Like Eminem once said, “How [are] you supposed to grow up when you weren’t raised?”

Though in pull-up-your-bootstraps 2007, there’s scant more loathsome than to grant leniency to such an example of drama and disaster embodied, it’s far too easy to sweep someone like her under the rug (in fact, consider this - the couple who made headlines last year when authorities discovered they were keeping their adopted, special needs children in cages were just sentenced to two years in prison this week. Sherry served three for doing heroin.) It’s too easy to discount her as a lost cause. It’s too easy to say that, just because she’s a convict, she’s a criminal. Because if the rest of us consider that perhaps she is the victim, even a little bit, then what, exactly, does that make the rest of us?