“The Greatest Showman” is a good old-fashioned cornball PG musical that is also a scintillatingly flashy — and woke! — immersion in up-to-the-minute razzmatazz. It takes the life of P.T. Barnum, the anything-goes circus impresario of the 1800s, who is played with irresistible effervescence by Hugh Jackman, and turns him into a saintly huckster-maestro who invented the spirit of modern showbiz by daring to follow his dream. At the same time, the film takes Barnum’s infamous believe-it-or-not attractions — Tom Thumb, Dog Boy, Tattoo Man, the Bearded Lady — and makes them over into sensitive enlightened outcasts, a kind of 19th-century freak-show gallery of identity politics.

How piously anachronistic is that? Very. Yet “The Greatest Showman” wants to give you a splashy good time, and does, and it’s got something that takes you by surprise: a genuine romantic spirit. The numbers are shot like electromagnetic dance-pop music videos, and to say that they sizzle with energy wouldn’t do them...