Why the bias of political ideology?

Why the bias of political ideology? 1. Why does political ideology makes a person a hypocrite? On June 6th, 1984, President Reagan delivered one of his greatest, most famous speeches, “The Boys of Point du Hoc.” Afterwards, he read the poignant promise inscribed on the monument in the Garden of the Missing: “To these we owe the high resolve that the cause for which they died shall live.” The cause? Freedom from oppression? In his 2005 book, according to our extant historian, Doug Brinkley, wrote: “the message is clear: These men fought for freedom against Nazism, so don’t we now have an obligation to fight against Soviet-style communism?” Why then does Doug Brinkley TODAY (2013) SUPPORT President Obama’s socialistic-style communism? I’ve heard him, I’ve seen the ‘sellout’ Brinkley extol and support the ‘transformational’ leadership of Barack Obama. Why does liberal political ideology make a person not only a hypocrite but an illegitimate historian?