Actually, Trump only fits into the middle because he doesn't belong on the chart. His position "evolves" quite rapidly for someone who doesn't believe in evolution -- oh wait, he changed his mind again, evolution is real! This guy is inconsistent on everything but his more racist, xenophobic, and chauvinistic comments.
He changed his position on abortion, and I'm not joking or exaggerating, FIVE TIMES IN ONE DAY! I watch Colbert's new show and he described Trump as "...He flip-flopped, then flap-flup-flooped!"
This is why Trump is in the middle of the graph. He changes his position rapidly to appeal to as many uneducated or ignorant people as possible, and he knows that his followers will still lap up whatever he switches to. Hell, Trump just took a standard Republican tactic and amped it up to the next level.