They're almost certainly #1 global problem causers so it's usually the safest bet. Though I wouldn't be as expansive as you, the USA, Portugal, Spain and the USSR are no slouches. Can't be forgetting the Dutch either.
So basically all powerful countries cause problems for other countries. Not exactly a resolutionary thing. Don't forget China, Japan, Mongolia, Romans, all sorts of infighting between native American groups before Columbus. And I assume that Africa wasn't exactly a paradise even before colonialism.
Yes, history happened and people should be held to account for it, not ad infinitum, but you know, if my dad killed your dad and took all his shit, and then left it to me, I'm pretty sure I shouldn't get to keep it and all the benefits that come from it just because I had nothing to do with it.
And how do you map that onto the timescales of states? Because even on the human scale, my grandparents were around for the British Mandate in Palestine. The British government had to win my own lifetime apologise for atrocities carried out in Northern Ireland.
The day my grandma went to school for the first day of her fourth grade, Germans launched an invasion on our country, starting WW2. During the process they set up death camps on industrial scale, and bombed our capital city to oblivion just to set an example.
My grandma died peacefully last winter. I think it's time to move on.
