1) All parents do not abuse their children, even in private and even when they wouldn't get caught if they were clever;
2) All bosses and teachers are not unkind, even in private and even when they wouldn't get caught if they were clever;
3) All stronger people do not abuse weaker people, even in private and even when they wouldn't get caught if they were clever; in fact, many of them go out of their way to teach, give, and help, and draw both a personal pride and a selfless pride from offering shelter and sharing knowledge.
It may be that "modern governmental power" corrupts, and it may be that corrupt people tend to seek "modern governmental power," but this is a far cry from "power corrupts." Naturally, a worthily-bashable dead white male was the one most popularly credited with the claim that power corrupts; even more naturally, it was one of the bloodviles, English royal line from some of the heights of the British empire. Descendants of Milton would, of course, fawn over the literary notion of "Satan," and love the idea that power must necessarily corrupt, freeing them of responsibility for millions of starving serfs, and the horrors of the state-funded BSDM chambers that still drive so much of their rotting tourist revenue today.
Oh, boo hoo, I did something wrong, but it wasn't me; it was power. If power corrupts:
1) You have no hope, because anyone who gets power will abuse it, so human lives will always be either powerless and futile, or terrible and tyrannical;
2) It is wrong to try to get power to help people, because you're not trying to help people, you're just trying to get power in order to be corrupted and abuse people.
See how neatly Lord Acton's axiom spoils the waters for the human future? If power corrupts, everything has to suck. We accept the American genocides because we've spent two hundred years believing that we can have nothing better, since any leader will necessarily be evil--and it won't be their fault, because it was the fault of an abstract philosophical concept. This is the kind of excuse you'd expect a PHIL 101 student to try when caught cheating on the final--"I had to look, because hidden knowledge requires a search for knowledge!"--but it's not the kind of excuse we should accept from our historians, our teevees, our leaders, or most importantly, ourselves.