What historical revisionism should be: Ah, yes, this is a new fact; let us see how this fits in with what we previously thought. Oh no, it does not, we should examine why and change our theory if needs be.

What historical revisionism should never be: The ignoring of attitudes of the day and the blackening of someone’s name without that context; the denial of any wrong-doing on your preferred side; the sanitisation and covering up of uncomfortable bits of history which make you question your world view.