And not so well for the Moriori[0]:

Moriori embraced a pacifist culture that rigidly avoided warfare ... On 19 November 1835, the brig Lord Rodney, a hijacked European ship, arrived carrying 500 Māori (men, women and children) with guns, clubs and axes...

A Moriori survivor recalled : "[The Māori] commenced to kill us like sheep.... [We] were terrified, fled to the bush, concealed ourselves in holes underground, and in any place to escape our enemies. It was of no avail; we were discovered and killed – men, women and children indiscriminately." A Māori conqueror explained, "We took possession... in accordance with our customs and we caught all the people. Not one escaped....." The invaders ritually killed some 10% of the population, a ritual that included staking out women and children on the beach and leaving them to die in great pain over several days.

During the following enslavement the Māori invaders forbade the speaking of the Moriori language. They forced Moriori to desecrate their sacred sites by urinating and defecating on them. Moriori were forbidden to marry Moriori or Māori, or to have children with each other.

[0] https://en.wikipedia.org/wiki/Moriori#Invasion_by_Taranaki_M...

Britain's destroyed economy after WW2 probably had more to it. A peaceful resistance can work against an enemy that is distracted with other matters, no longer interested in occupying, or demoralized. In the case of India, the UK managed to maintain business connections quite well in the region and colonialism was becoming outdated and expensive to broke Europe.

Agreed. Although he did have to count on the British having a sense of morality. I'm not sure that exists at the top-level in the PRC.