Years ago I just thought history was. In the intervening time I have found out that it seems to vary quite a bit depending on who you want to hear, and what their agenda is.
Things that people don't want to talk about, like Kennedy stopping the air and naval support for the Cuban freedom fighters, don't get mentioned much, if at all.
I've come to appreciate Orwell's perceptiveness on the subject.
"Those who control the present, control the past and those who control the past control the future."
Orwell hit the nail on the head.