UPS uses this in the direction software their delivery vans use. minimization of left turns means the vans get everywhere faster and more packages are delivered in a given day.
Why is it like this? The only valid reason I can think of is that turn lanes would tend to back up at most lights in busy cities. I would think correcting this behavior would help reduce the number of vehicles turning, to offset the backup.
This does seem perfect for most Midwestern highways where space is not really a concern and traffic is relatively light.