Good and evil have little to do with it. The British abolished slavery in their colonies because it was no longer profitable but it was still profitable for their global rivals, the French and Spanish. They dismantled their empire because they could no longer afford to maintain it. This does not mean they are bad people, it just means they are like everyone else.

I'm willing to concede that some policies, or some regimes, are "better" than others, but when you start teaching history as a good guys vs bad guys soap opera, the truth gets left behind. It's not that it doesn't happen, it's that the story is always more complicated than that.

As a Southerner, my high school version of the "War Between the States" was that it was an economic struggle for supremacy between the North and South, and that the North resented the South's agricultural power so it started the conflict (although it was the South that fired the first shots). Slavery was barely mentioned, except to point out that "some slave owners treated their slaves decently". I see now there is some truth to this, but I also see that it was not the whole story.

Once you get safely far enough into the past, or far enough away that the participants are not consulted, you stop seeing good guys and bad guys and you just see conflict and rivalry. Compare any recent history of the First World War with one written shortly after the conflict ended. Today it is pretty well conceded it was all about colonial rivalries, a topic not even mentioned in post war analyses written by either the victors or the defeated.

I'll be the first to agree that the instinct to be fair and objective can be carried to ridiculous extremes, but that doesn;'t mean we should abandon it altogether. As much as I admire the English and their phenomenal accomplishments and contributions to world civilization, I have also read their history and know it to be a very bloody one. And you don't have to just survey the brown and black and yellow peoples they conquered, enslaved and exploited; ask the Welsh, Irish, Scottish and Americans they once ruled, too.