While watching Josh Kreigman and Elyse Steiner’s documentary “Weiner,” I kept asking, “Why?”

The movie is the story of Weiner’s attempt at a comeback after resigning from Congress (7 terms) because he sent pictures of his junk to several women. As he runs for mayor of New York, we see him trying to convince people to give him a second chance through the ups and downs of campaigning, raising money, and battling the tabloid press (which loves the story of his sexting alter ego, “Carlos Danger”). We’ve rarely seen someone in the midst of a scandal from this point of view.

But why would Anthony Weiner and his wife, Huma Abedin, allow cameras to capture the lowest moments of their personal — and his professional — life?

He relishes the fight, but it’s very tough to watch Abedin suffering. At one point, one of the documentarians asks her how she’s doing and she replies, “It’s like living a nightmare.” As a top aide to Hillary Clinton, she knows none of this is good politically. Her sorrow and disgust make it clear she regrets allowing cameras into her home and her life.

Meanwhile, he is too feisty and short-tempered for his own good, and doesn’t know when to keep quiet or back down. There’s a scene where he’s talking with some New Yorkers in a bakery, and it hasn’t gone well, so he’s leaving. He’s through the door and only a few steps away from the car that will whisk him away when someone says something ugly about him. Weiner doesn’t have the political discipline to simply get in the vehicle and get out of there. Instead, he turns and confronts the man face-to-face. It’s not pretty and the cameras — from both the movie and the local TV stations — capture the whole thing.

There’s even an appearance by Sydney Leathers, Weiner’s sexting and phone sex partner who exploited her 15 minutes of fame with a sex tape.

In the end — as the negativity about the man and his campaign mounts — even the documentarians can’t believe Weiner allowed them to film all of this. But I’m glad they did.

I give “Weiner” a 9 out of 10.