Anyone that has been in leadership roles at work understands that people that report to you are motivated in a variety of ways. For some you can dangle an incentive in front of them and they'll work like crazy to earn it. With others you have to use a pit bull approach and light fires underneath them from time to time. Calling them out and putting some public pressure on them causes them to rise up. While others need positive reinforcement or even false praise from time to time so that they feel motivated to live up to the encouragement and support they know they deep down don't deserve.
Bronco respects Howell's loyalty, hard work, and attempt to accomplish a tall order that was asked of him last year. It was Bronco's fault for asking too much of a willing staff member who wasn't prepared enough to exceed at the job. That's not Nick's fault. So Bronco is publicly sticking by his guy who showed a tremendous level of loyalty and took the brunt of the public scrutiny last year. Bronco knows that Howell has all the motivation in the world now to become better and step up his coaching. No need for bronco to call him out in a negative way at this point. They know how last year went and they've corrected the ship. Bronco is over the D and Howell is back in learning mode.
Seems few people understand this kind of stuff.