I agree that's a skill that many people lack, including me.  Maybe the people who score more highly on the "justice" than "mercy" domain on personality questionnaires?  The ones who haven't quite outgrown the "But it's not fair!" indignation?  There are some real sharks in some workplaces that look for any advantage, any weakness in their colleagues.  If need be, they'll invent one, all to make themselves look good to the boss.  Some people are much better at playing the game than others.  It would be great if we could all have a class on that!