If a person were to read the newspaper, they would figure out that Trump is a pathological liar, but most don't read a newspaper, and even among those that do, a lot of people read for confirmation rather than for understanding.
A lot of people get their information from Fox News, right wing radio, or right wing leaning podcasts. These information sources direct your focus to things which will make you angry about the things they want you to be angry about, and ignorant of things which maybe you should care about.
The most important things which we can all do is to take back control of our own focus and maintain our sense of curiosity and a dash of healthy skepticism. Ask why someone is trying to get you to focus on this or that. Ask why they never mention these other issues which may be equally or more important. Question your own biases and assumptions from time to time.