I am well aware of Britain's so-called neutral stance, or "splendid isolation" as it used to be called. But, as you have already suggested yourself, it only referred to mainland Europe. This was because the mainland Europeans had to fight over limited amount of territory to maintain their empires, while the British, with their dominant navy, could more easily rape and pillage the more "backwards" parts of the world, including and by no means limited to, Ireland, the Indian empire, Africa, China. There was hardly (if any) a single year in the nineteenth century when the British didn't have to fight some war or insurgency somewhere.
Nevertheless, Britain of course still interfered in Europe, including the Napoleonic Wars and the Crimean War, because, as you say, it was necessary to keep the European opponents in balance so Britain didn't risk losing its dominance. Considering the size of both these wars, "splendid isolation" or "neutral stances" begins to look like the wild fantasy of some old duffer colonel.
Your last paragraph is so wrong from beginning to end, that I won't bother to address it, not least because I don't have the time. I have found an article which briefly discusses some British atrocities (and not even a mention of the Irish famine!!) -
http://www.hindu.com/2005/12/28/stories ... 961100.htm - what with Google, you can easily follow up some of the stuff he refers to in there. You should also try reading George Orwell's "Not Counting N*gg*rs" - it's a short essay, and it's easily available on the internet.
If you really think you can criticise the USA by comparison to the British Empire, you are on very thin ice. The USA has caused the deaths of many hundreds of thousands of innocent people, but that is chickenfeed compared with the British in the last century-but-one.