Just ask them why three times in a row no matter the reasons they give. It will make them uncomfortable and maybe cause them to actually self reflect and give you the satisfaction of watching them squirm in their cognitive dissonance. Then change the subject to non political matters and have a nice time doing whatever you were doing befor politics came up.✌️ 

 More socially acceptable to the Japanese approach of 5whys for root cause analysis!!! I like it.