People who think Bonner somehow disproves plus-minus are clueless. The fact that Bonner carries an elite score in that stat despite being at best a mediocre player underscores how powerful his position is. Bonner headlined an entire movement as a stretch-four. He was one of the first guys to show that having a shooting big could work, and furthermore that it can run a twin-towers lineup off the court. He's the reason why Memphis is a dinosaur, who finally seems to have started the change with Green starting the last game.
Plus-minus doesn't suggest that Bonner is a great player. It does suggest that he's a match-up problem.