The Framers deliberately kicked the can down the road on the question of slavery. You are not a stupid person, though you give it the old college try, so I figure that you're doing this two-step for a reason. So let's hear it.
Thomas, for those of you who aren't as deeply informed as PB, was the descendant of slaves. He was born and raised in Georgia.
And here I thought you'd be going for the 3/5ths clause.
They weren't trying to have a document that was a be all end all. They knew insisting on the elimination of slavery would mean they wouldn't get an agreement. As they say, politics is the art of the possible.
Look, the Articles of Confederation weren't working anymore. They needed a new agreement among the 13 independent former colonies for a lot of reasons, one being excessive taxation for goods being shipped through some states on their way to other states. At a time when they were surrounded by often hostile forces - the British, the French, and the Spanish were all in the area, among others, and often at war, pirates, the Indians to the west, they needed a collective security arrangement. It expanded from there - they wanted to present to these neighbors and the rest of the world a united front, and did so with the creation of a federal government that was given these powers.
Have you ever even read the document? It mostly sets up the House, Senate, presidency, and Supreme Court, and their duties, and some other relevant issues regarding the formation and continuation of a government. The Bill of Rights - for all of us - came later. Slavery wasn't an issue because it wasn't going to get resolved then, they'd already taken on an almost overwhelming amount of issues in order to regulate trade, resolve disputes, etc, and secure the new nation states.
So yes, they kicked the can down the road. Just like every other piece of legislation that doesn't address everything on every issue under the sun.
Clarence Thomas thinks it's a brilliant governing document, and until someone can produce something better, thinks we should stick with it. Regardless of it's flaws.
But you're saying he's black, so he isn't entitled to think that?
If you have any more questions, can you take them to the Politics section?
