Well the British made slavery illegal in 1772, made the slave trade illegal in 1807, and policed the world in attempts to eliminate all slavery from the 1833 Empire-wide laws. Probably a high point in the history of human (moral) development.
Since the end of colonialism and the British Empire, and the implementation of monetarism and incentivization and “anti-paternalism”/economic liberalism* in Western societies, I would say we, as a global society, are a lot worse off morally.
Compared to the later days of the Empire.
*economic liberalism: letting corporations do whatever they want… awesome.
Sure, the USA was still in the Dark Ages WRT human rights, and some European countries were incredibly inhumane in the management of their colonies, but others (the British) genuinely wanted to develop the colonies into better, wealthier places. We were even beginning (just about) to learn about and respect the cultures of the locals.
the end of Empire was often justified by saying it is “just wrong”. What was done in the name of Empire was very often wrong, but that doesn’t mean the Empire was necessarily always going to be a bad thing.
The United Kingdom at the time was the most socially progressive nation on Earth, and the labour laws eventually made it more far more a worker’s paradise than the Soviet Union. These ideals and rights and morals were beginning to, and would inevitably have eventually, spread to the Empire. That didn’t happen.
The end of the European empires was engineered by a US-biased UN, which wanted all restrictions on corporate practice around the world to be removed, so the exploitation of the wealth, labours and resources of the colonies could be undertaken, unimpeded, by US business interests.
This didn’t just mean no tariffs to be paid to the British, but it meant no (effective) laws to obey, no standards of safety, no guarantee of workers rights, no forced contributions to local development, etc.
Look at the post-colonial (American) methods of wealth extraction from the ex-colonies. There is no intent to develop or educate or help the local population, or build sustainable industries.
There is no restraining and guiding hand of elected and morally-motivated government.
There are only trans-national corporations, corrupt war-lords, and filthy profiteering.