The English weren't much different from any other nations. Remember the scramble for Africa, with Germany, France, Belgium and Portugal all grabbing land and resources - a scramble for which the people of Africa at still paying the price today. Look at the Congo, Angola and many other places...then look at India, Australia etc.
That is not to excuse Imperialism - it is exploitative and generally to be condemned, but it has to be put into context.
And (he whispers quietly for fear of offending), didn't America have her own imperialist intentions before the First World War, with a view to a Pacific hegemony?
The problem is, the English have copped the flak for the Empire because they had so much of it, and because one of the most shameful episodes - the Famine - affected a population which went in droves to an anglophone country with its own suspicions of perfidiious Albion. Maybe those suspicions were justified - after all, there was pressure from British business interests to intervene on the side of the Confederacy to maintain the cotton trade. Thankfully it was resisted - maybe because the majority in the UK had already decided that slavery was abhorent, but probably because any economist or strategist realised that the South's was a hopeless cause and that the future lay in industrialisation - but that's for another day... :^) All of which is why, today, people bang on about the nature of the terrible Brits. As, in some parts of the world, they bang on about the terrible Yanks. After all, when Kipling wrote "Take up the white man's burden..." he was actually addressing America.
Think on't as they say!