Countries which use left hand drive drive on the left side of the road account for only a sixth of the world's land area, but a full third of the population.
I suppose that's because left hand drive driving on the left has some very dense populations, like Japan, UK and India
I think you’re getting confused by the terminology; this is an explanation from the Wikipedia article.
The terms right- and left-hand drive refer to the position of the driver and the steering wheel in the vehicle and are, in automobiles, the reverse of the terms right- and left-hand traffic.
ETA: So the red areas have left-hand drive and right-hand traffic, while the blue areas have right-hand drive and left-hand traffic.