I was in the right lane behind an SUV going 100.  Another driver ahead
was going 80, so I followed the SUV driver into the centre lane to pass.
 Suddenly, the SUV driver started slowing and not moving back to the
right lane.  The problem was a CLB that was slowing to match speeds with
the slower car.

The SUV driver swerved around on the right and accelerated away.  I also
passed the CLB on the right, accelerating away and then returning to my
original speed.  About a minute later, the CLB was speeding up and was
playing Duckling next to my rear.  The approaching traffic was going
about 140, and this Duckling was making me part of the hazard.  Drivers
were swerving around on the left and cutting in front of the CLB.  The
CLB then started driving directly next to me.  I honked at the CLB, but
instead of speeding up and moving to the right lane, it passed me to
play Duckling in front of me.

Before the next bunch of drivers started to pass, I accelerated away
from the obstruction.  The approaching traffic quickly noticed the CLB
in the lane.  Drivers started swerving around on both sides, and as the
first few drivers passed on the right, the CLB did something even more
stupid.  The CLB drifted into the left lane, causing the drivers who
were passing to brake hard and swerve back to the centre lane.  Traffic
was quickly jammed as confusion slowed all of the traffic behind the
obstruction.

Why can't they stay in the right lane except when passing?