It's not about political correctness. It's about what these people make you feel, and how you respond to it. People want to believe that somebody whom they like on one score - Linus's technical achievements, Donald Trump's ability to empathize with the working class and the poor - are likable on all scores.
It's much like the classic literary 'harsh father' figure - he may beat you, he may be strict, he may never show love, but he provides for the family and he teaches you to be moral, so everything he did must have been good. The beatings must have had a purpose. It's hard for us to accept that good and bad exist in the same person, and that somebody who does good things may also do very bad things, not just discretely, but often at the same time.