The technical term comes from archery. In archery, the arrow rises when fired, so when shooting at very close targets, you actualy aim lower than the point you want to hit. At distant targets, of course, you aim higher, because the arrow will start to fall.
"Point Blank" is the distance at which you aim directly at the target. Last time I did any shooting, it was about 22 feet, with my bow and my arrows.
What's our alternative? Roll over and let the fascists take over?