I think I read that collision was about 0403. This would've been change-of-watch time for the typical large ship, and the relief of watch can be a distraction from lookout. Seems many collisions happen at 8, 12, and 4 as a result.
And ships usually show some house lights aside from the nav. lights, while a sailboat, even a large one, may show only a white stern light if you're overtaking her, and a white light is easier to lose in background lighting ashore than the red or green would be if you're meeting or crossing.
These are just general observations, I'm not trying to speculate here since we don't know the facts, just the result.