Because they were expecting $45 million on opening weekend alone. I bet they were expecting somewhere in the neighborhood of $75 million in total revenue.

What Sony could, and should, do, IMO --- leak a poor quality version online. People will download it and Sony can be outraged. North Korea will buy that it wasn't Sony who leaked it and scream and cry, but not take any more actions against Sony. In six months Sony should release the movie on legitimate streaming services. The noise will be minimal, because everyone will already know that the movie was available online for so long. North Korea won't get in a tizzy because they'll figure that it's already been available, so there isn't any additional damage being done. After 3 months on streaming services, release the DVD.

I think it's the only way Sony can hope to recoup any of the production costs. The movie will probably do pretty well on streaming services and DVD because a lot of American's won't download the movie illegally.