Dwight staying for another year is NOT about loyalty. Its business and a lack of mental toughness.
Business because (from what was published/rumored) the Magic had finally made the decision to trade him. That means he had lost the upper hand, and was no longer going to choose his destination.
Lack of mental toughness, because he made his decision to sign back right when the media turned against him. Before his "roll the dice" comments, he was never really cast as the bad guy. Once that happened and he started to be vilified in the media, he got scared and flipped his position. He was scared of becoming post decision Lebron, and seeing his jerseys burned when he left.
Loyalty would be to put everything aside, and sign an extension. If you REALLY want to show loyalty, and your only concern is having a better team around you, you sign an extension for a slightly lower amount than you could potentially get (like westbrook), and let the team spend the rest surrounding you with talent.
IMO, Dwight Howard has shown himself to be a coward for the way this had unfolded