The answer is "wanting to disguise the truth they have uncovered."
Some historians find this tough. One of the reasons would be because not all people may or may not, like the truth. Some historians would omit some part of the truth to keep violent reactions from the readers or outsiders.
The economic value of having colonies in the first place was for 3 main reasons
1) attain cheap labour from the native peoples
2) acquire cheap raw materials to bring to the homeland (Europe)
3) open up new markets to trade with
the first two were vital in Britains industrial revolution. Without cheap raw materials, and cheap labourers, the factories and refineries in Britain would have costed far more to maintain and keep supplied. This, in turn, would have slowed down production considerably. There is no doubt in my mind that the industrial revolution would still have taken place in Britain with or without the colonies, but WITH the colonies the process was sped up considerably.
Overall, cheap labour and raw materials attained through Britains colonial interests sped up the industrialisation of the UK.
They fought for independence and freedom
