"As long as the reason of man continues fallible, and he is at liberty to exercise it, different opinions will be formed." - James Madison
This simple statement shows the function of liberty in a society. It is true that some people in a free society will make bad decisions and may use illogical reasoning to justify their act. But as long as we are truly free to exercise ourselves and free to watch others and see what works, we will come to newer and better conclusions without the need for an oppressive and authoritarian government.