Why do we use Genuis's quotes,wheter they were good quotes,or not?

Casually,to make any point?. In other words,everything a person says is not always brilliant,or correct.Just because aperson may be smart aand knowledgedgable in one area,or subject does not mean that they are all knowledgeable, or even inciteful. Isn't it possible that a genious can suffer from a sort of "Tunnel Vision"? For example: Using Albert Einstein's Quote: "Science without religion is lame,Religion without Science is blind". Well, if he were alive, one might argue with him that, it is a fact that Science is based on Science and has no religious merit ,as Religion has no Scientific basis. So, his Quote has no validity and never has.. I don't think his idealism counts here,does it?