The word for the day. The Oxford Dictionaries define the word "demagogue" as "A political leader who seeks support by appealing to popular desires and prejudices rather than by using rational argument" or anyone who uses those tactics. Alexander Hamilton, in both his introduction to and conclusion for the Federalist Papers, warned about the dangers of these types. The aim of the Constitution was to avoid them.
Mind you, it is not the appeal to emotion and prejudice that is the problem. A situation logically explained can certainly produce emotions and prejudices. It is the appeal to emotion and prejudice to the distortion of logic that is the problem. A prime example in history would be the McCarthy era where an irrational furor over Communism spawned the House Un-American Activities Committee and the political equivalent of the Salem Witch Trials. Not reasonable; demagoguery. A modern example is Donald Trump's Wall. Yeah, right. We'll build a wall from California to Texas and make Mexico pay for it. That might make some people feel better, but it makes no sense. It isn't rational; it's demagoguery. Then there's the whole "transgender" thing. Logic demands that XX is female and XY is male and we're done, but emotion cries out for "how we feel" and is quite pleased to arrive at compassion for the XX trapped in and XY body or vice versa until we cannot define gender at all. This isn't rational; this is demagoguery.
Politicians delight in it. Various causes are rife with it. Entire movements and even governments are built on it. Appeal to their emotions and their prejudices and you'll win the day ... even if you're dead wrong and even dangerously so. And it's not possible to argue against it because you're arguing logic against their feelings. That is, if you are right they'll be miserable. Good luck with that. You'll find this in the liberals and the conservatives, the atheists and the religious, the left and the right. Don't let it be you. We are to "love the Lord your God with all your heart and with all your soul and with all your mind." (Matt 22:37) We are to "be transformed by the renewal of your mind." (Rom 12:2) You might not always be able to fix the demagogues or those who fall prey to them, but you can be sure you aren't among them.