How and why did the belief emerge that the British Empire was uniquely benign compared to other empires? And how, operationally, does it persist?

I try to be dispassionate and treat empire as the complex historical phenomenon it was, with many shades of nuance and few absolutes. A spectrum, with collaboration or acceptance by many of the governed, murky motives by many liberation fighters, as well as a blurred line due to the partial integration of semi-metropolitan colonies with strategic significance, such as Ireland, Algeria or Cuba.

But (speaking of the case I encounter), it does always seem striking how emotional and defensive a reaction is provoked by fact-based analysis of British authorities' historical events in a supposedly civilised age: actions such as internment without trial, collective punishment, and the use of force (in my period, the interwar, see e.g. Ireland, Palestine, Iraq), which would have been deemed arbitrary and tyrannical if carried out by other European nations - or within England itself.

To what extent is this perception influenced by selective national narratives and romanticisation, e.g. from a top-down direction (school curricula, etc.)?

Is there parallel "imperial nostalgia" in other post-imperial nations like France, Russia, Japan, Belgium etc., i.e. romanticisation of the benign and beneficial side of empire, and a defensive or emotional knee-jerk response to assertions to the contrary?