The post (on FB, sorry) explains that Trump supporters see Trump as fundamentally honest, and Clinton fundamentally dishonest because (among other reasons) Trump “speaks his mind” and Clinton does not.
And since Trump supporters disproportionately distrust mainstream media, politifact and other fact checkers have little effect.
From the post:
“Why have Trump and Clinton supporters found it so difficulty to empathize with (or even understand) the other side? I had no idea why, and had a lot of trouble understanding both sides myself (even after reading many articles on the topic of how Trump and Clinton supporters differ).