I have trouble with the hagiography of Martin Luther King. Yes, he was a great man who did a great thing for which he should be duly honored: he was an inspirational figure in the non-violent civil rights movement in this country, as well as a remarkable speaker.
The two, of course, are related. It was his personal qualities of leadership and what George H.W. Bush might rightly call “the vision thing” that enabled King to bring together so many people to peacefully demonstrate in furtherance of a lofty and necessary goal, that of ending discrimination against blacks in this country.
As for the rest of it—well, I think it can be summed up by saying that King was a flawed human being. Perhaps MLK himself would be the first to agree; he was a preacher, after all, and he knew a lot about human sin and error. It’s pretty much certain he was a philanderer as well as a plagiarist, and in later life he seemed to veer ever more leftward (some think that’s a feature, not a bug). Does that diminish his achievements? I don’t think so, if we keep it in perspective. I’ve always been more interested in real human beings who accomplish great things despite their own weaknesses than I am in a pretended (and mostly unachievable) perfection.
[NOTE: One thing that's long amazed me is that King was so young when he was assassinated. At the time I thought him a man in his 50s, but he was actually a mere 39 years old. If he were alive today, he would only have just turned 83 yesterday.
There's a lot of speculation on what King would have thought of current trends had he lived. I'm no expert on everything the man wrote and said, but it's my impression that although he seemed to be in favor of some sort of reparations---which he did not limit to blacks, by the way---he would not have backed affirmative action or gay marriage. However, people do change---as I know only too well.]