Historiography is the history of history, how it's been tweaked and edited over time.
The teacher in Billy Collins's poem The History Teacher blatantly lies to his students in an attempt to protect their innocence. Of course, the poem is an exaggeration, but there is underlying truth.
Even today, we're constantly deceived by everything from advertisements to the government. Look at how complicated these FDA requirements for food labels are. Is this really necessary? And what about the U.S. national debt? The last time I remember hearing anything about it, it was around the $7 trillion mark. Now it's all the way up to $17 trillion, and climbing steadily.The list goes on and on. Overfishing, foreign political issues, you name it.
Historically speaking, governments tend to sugarcoat the truth for the sake of "protection." Like The History Teacher shows, though, it doesn't actually help. Ignoring and covering up real issues actually makes things worse in the long run, akin to festering wounds. We've all learned this lesson at some point (after a stern scolding in preschool, for me). Recognizing the problem is the first step to solving it.
Personally, I think we'd all be better off if people stuck with the truth.