Since at least the Enlightenment and perhaps before there has been this notion that our current state of affairs requires the justification of history; or else lacking that the present order is nothing and can be discarded. If injustices were perpetrated against the American Indians, the narrative goes, then the entire present order of private property in America is called into question. If the Hiroshima bombing was immoral, the narrative goes, then entering the war in the first place was unjustified, and indeed the American military and American efforts to defend herself from foreign aggressors is morally suspect generally. If the conditions for a just war were not met in Iraq at the outset, then no obligation to use military power in the present context is metaphysically possible.
Most on the political left and many on the political right buy into this narrative, taking it as true and drawing a conclusion about the major premise from a self-serving reverse-engineering of the proposition. The left likes the idea of invalidating the present regime of private property and of castrating American defense, so therefore the major historical premeses above are true. The right (correctly) resists those conclusions, and therefore (incorrectly) concludes that the major premeses are false. Many on the right conclude that simply agreeing to the major premeses above constitutes "liberalism", as if liberalism is inter alia implied by a particular assessment of the justice of specific historical acts.
It is an odd view of history to take a particular positive reading of it as necessary for justifying grace in the present order, and anyone who holds to the view ought to take a step back and reevaluate. Locke's justification of private property (to the extent I understand this part) is fundamentally flawed: no attempt to revert to a state of nature and man's addition of value to it can justify ejecting a particular trespasser from a particular piece of property, nor should anyone be foolish enough to buy into the premise that this is required and attempt such a justification. The metaphysical conditions which give rise to the attempt to justify private property in this positive-from-foundations way don't exist. The world as such requires no justification; the particular acts of men in the positions in which Providence has placed them do. To ask the world to justify itself through history is to beg for death, because there isn't a living soul today whose very existence is not stained by historical sin. Not one of us would exist at all if men in the past had not sinned.
Among men who attempt to turn war cries from particular conflicts into fundamental principles of order it isn't any surprise that a positivist reading of history as justifying sacrament (or the lack thereof) easily takes hold. But that isn't wisdom, it is folly.