The true-life story from which this Oscar-winning movie is taken may well be every bit as inspirational and remarkable as its fans believe it to be. But the film itself is dead from the neck up and the neck down: a Photoshopped image of reality that is bland, parochial, and stereotypically acted by a cast who have nothing like the subtlety and range of Trey Parker's puppets from Team America: World Police. Sandra Bullock got her Oscar for playing the tough-love Christian Republican wife and mother who takes in a troubled African-American teen and motivates him to greatness on the football field. Her performance is dominated by a strangely humourless glazed expression – the same with or without sunglasses – an intermittent clenched smile and a frosted blond do that looks as if it would splinter if you chipped it. There is something weirdly absent about this performance, which seems to have been been co-sponsored by Percodan, with additional vexed walking-and-talking-while-on-cellphone brought to you by Klonopin.

Her easygoing millionaire husband Sean (Tim McGraw) is too good to be true, her cheerleader daughter Collins (Lily Collins) is pure whitebread, and Collins's kid brother, tousle-haired little tyke SJ (Jae Head), deserved some sort of mini-Oscar for being annoying. Bullock is Leigh Anne Tuohy, the formidable woman from Memphis, Tennessee, who one evening notices a big, unhappy black boy called Michael Oher (Quinton Aaron), shuffling out of her son's school with ragged clothes and, apparently, no place to sleep. She takes him under her wing, into her home and into her heart. There are pre-emptive scenes coolly nipping any worries in the bud – she raises and dismisses the fear that he might steal something. A friend is icily rebuked over lunch for wondering about Michael's proximity to Leigh Anne's lovely teenage daughter ("Shame on you!"). Leigh Anne herself seeks out Michael's drug-addicted mother and, without needing to ask, secures the woman's heartfelt blessing for what she is doing: "You're a fine Christian lady!"

Soon Michael is taking to the football field and, after a wobbly start, is a natural and definite college sports scholarship material. But wait. Like all the Tuohy family, Leigh Anne loves football. Could it be that she was grooming Michael as a mouthwatering gift to her football-crazy alma mater, the University of Mississippi, a big part of her social status and the place where she undoubtedly hopes to send her own kids? And if she was, what on earth is so bad about that? Everyone wins, don't they? Aren't conservatives allowed to show compassion? Especially as Leigh Anne's compassion, unlike that of whingeing liberals, actually gets things done?

That is the only real dramatic issue at stake, the only question that might smudge the family Christmas card perfection of this story. The movie fudges it – it is raised, perfunctorily, only at the very end. The rest of the action is taken up with predictable, hammily acted nonsense. There is a rich, complex story to be told about Michael Oher, and his mentor, Leigh Anne Tuohy. But this waxwork parade isn't it.