It's history written to a purpose. If you read Thomas Macauley's History of England ( or, for that matter, Hippolyte Taine's history of the French Revolution ) you will notice that the author is constantly present as a critic and commentator, not just a narrator, very much telling you what to admire and what to condemn. This would later be satirized in Sellar and Yeatman's 1066 and All That, ( 1930) where there's lots of Good Things and Bad Things , e.g. " Henry VII was very good at answering the Irish Question, and made a Law called Poyning's Law by which the Irish could have a Parliament of their own, but the English were to pass all the Acts in it. This was obviously a very Good Thing.".

Providing moral instruction- especially to the young- the "Whig School of History" paraded models to emulate, villains to despise, and a narrative of constant and comforting progress. It spoke to the people who felt they were in charge, were going to be in charge. Yes, the Middle Ages were superstitious and violent, a Bad Thing, but they did try to put Christianity back in charge of the Holy Land, take it away from those Arabs and run it properly , a Good Thing. Macauley would be very influential in the way the British set up education in India, wanting all classes to be taught in English, and only Western subjects. As he would say in his Minute on Indian Education, :

it is impossible for us, with our limited means, to attempt to educate the body of the people. We must at present do our best to form a class who may be interpreters between us and the millions whom we govern; a class of persons, Indian in blood and colour, but English in taste, in opinions, in morals, and in intellect. To that class we may leave it to refine the vernacular dialects of the country, to enrich those dialects with terms of science borrowed from the Western nomenclature, and to render them by degrees fit vehicles for conveying knowledge to the great mass of the population.

There's racism here, obviously. Westerners are the peak of civilization, someday under their paternal guidance the savage barbarians might be improved. There would be similar language employed by apologists for slavery in the antebellum US (, and defenders of Jim Crow laws postbellum) that civilized whites would guide uncivilized browns and blacks until the whites had judged ( some day) they were ready. One of my personal favorite images of this attitude is the jacket design of Henry Morton Stanley's In Darkest Africa, with a tall Stanley, angelically white, his hand on a dark, submissive and diminutive African.

But this didactic emphasis on white progress required some silence. To discuss the immense amount of money England actually earned from slave labor in the 18th c. was to raise the uncomfortable possibility that it was a Bad Thing that funded a lot of nice estates and ships and armies and wonderful garden parties - their Bad Things paying for our Good Things. And of course, that might lead to thinking that perhaps the money extracted from the labor and property of the natives of colonies, like India, might also be their Bad Thing funding our Good Things. For creating young , ambitious colonizers of the future, that was a very Bad Thing to teach.