That's right. Drivers in the left lane know that they have the added responsibility of looking behind as far as they can see and be ready to move over. Unless you have a fast car, you use the lane for passing. You move to the right immediately after passing.
You'd be surprised how fast those flashing high beams just on the horizon are suddenly right on your tail.
In Canada and the U.S., drivers think it's their right to drive in the passing lane at the speed limit (or even below), completely oblivious to what is behind.