Container ships have tremendous mass and with it, inertial force. A large ship steaming at 15-20 knots would require more than five miles to stop if they put the engines into full reverse. Likewise, it would take several miles to make a 90º turn.

Conversely, the warship is not only smaller, it's far more agile by design. This is not to discount its size but it's intended to be more maneuverable.

Something went seriously wrong on the bridge of the destroyer.

or asleep at the helm as the case may be....

Those are big ships, and they aren't designed for maneuverability. In all likelihood, the navy ship made a mistake and didn't respond for some reason. It was probably the more maneuverable of the two.

It was probably taking the most vigorous evasive action possible.

By all accounts, he was asleep in his bed. Unfortunately for him, even when he's not on the bridge, he is "in command". His career is almost assuredly over. Right, wrong or otherwise, there are a few cardinal rules for navy captains. Getting struck is a big one, even if it wasn't technically "your fault".

(Another one is running aground. There's an interesting story about that from D-day on Omaha beach)