Nope, I have been all around the world and have met many people who speak English as a second language with a British accent. Also saying you 'perfected it' is the one of most stupid, arrogant things I have ever heard, also it is an opinion and subjective.
Also, 'Might does it make us right' ... Is an awful philosophy, and also arrogant as well. What other types of people throughout history have used that philosophy?
I've lived all over the world, and most accents of people I met who spoke English as a second language sounded like an odd regional accent that came from their inflections of their native tongue and pronunciation seeping into their speech. As well, many who talk to me always ask about the American cultural and media depictions for which they picked up the language in the first place, so they typically use American pronunciation of certain words. 
You saying that we didn't perfect it is an insulting and demeaning statement, and of course is an opinion and subjective. 
Not really; it's been the natural philosophy since time immemorial. Seriously, it's the might of the winners who gets to decide what is and isn't right. What types of people throughout history have use that philosophy you ask? Well, for starters, the British... 
And the Romans, and the Germans, and the Greeks, and the Persians, and the Mongols, and the Americans, and the Spanish, and the French, and the Soviets, and the Japanese. The answer is: who hasn't?