Also people who emigrated from India to other British colonies benefited - that includes my ancestors.

British rule also got better over time. It also depended on your point of view. For low castes it probably did not make much difference who ruled - and the British may have been better for many of them. Another feature of British rule in India (and elsewhere) is that it was only possible because of Indian support. The same was true in Sri Lanka - Leonard Woolf's account of his time there is fascinating and British rule was not maintained by force of arms - he comments there were hardly any soldiers outside the capital, and the police he relied on were "native".

Its not whether it was right or wrong - I do not think conquering other people is can be justified. It is that it just is and its consequences are inescapable. Its like the Roman conquest of Britain and most of the rest of Europe. Bad things, can have good consequences.