First, these ride times don't include pre-shows which will add a few minutes. In the case of Soarin', Space Mountain, Splash Mountain or Star Tours, it doesn't factor in the 10 mile walks to actually get on the rides. That's an exaggeration, but it can be a hike. These are the times from when you're seated, buckled or harnessed in. In the case of the Circle-Vision movies, it's how long you're going to stand.
Picking the wrong ride at Walt Disney World can really mess up a schedule. You see an attraction, doesn't look like there's a wait so you think 'great, we can squeeze this in before we head to our dining reservation.' Well, if you picked 'Ellen's Energy Adventure' you just committed yourself to 45 minutes. (While some rides are easy to bail out of, this isn't one of them.)
The more eye-opening use of the list is seeing how long you wait for a ride that's over in an instant. Still, those minutes are magical and in most cases, well worth the wait.