It does no such thing. Their own writings show conclusively that they were aware of the contradiction and regretted it greatly. They just didn't know to get rid of the institution safely. Since we're still dealing with the aftershocks of its abandonment, it's hard to argue with them on the point. Most deceived themselves that it would gradually fade away with no effort on their part. Given the economics of the institution in the late 1700s, this was not unreasonable.
The notion that the Founders did not think the principles of the DOI applied to Africans is the rationale behind the Dred Scott decision. It was conclusively refuted in the dissents to that atrocity, and many, many times since.
Ever since the civil war, people in the North wanted to believe the war which killed 600,000 people was fought for a noble purpose. It wasn't. That noble purpose got tacked on towards the end to justify all the bloodshed which occurred.
A classic example of projection. Secession and war by the South being about much of anything other than slavery was indeed an after-the-fact rationale to justify a war fought for an immoral cause.
It should also be noted that the destruction of the institution of slavery was NOT "tacked on towards the end" of the war. It was a continuous process that started within a couple months of Sumter and continued thru Dec. 1865. Notably, the preliminary Emancipation Proclamation was issued 16 months after Sumter, 31 months before the war ended. I don't see how that qualified as "towards the end." I produced a Timeline of Emancipation once that spelled out this gradual and continuous process by month. I'll see if I can find it to post.
Again, the abolishment of slavery did not motivate the North to fight the war, but it did give them a moral justification for getting so many people killed in the pursuit of an immoral purpose, AFTER. THE. FACT.
Again, projection.
I contend preservation of the Union was NOT an immoral cause, even divorced from the abolition of slavery. It tested "whether that nation, or any nation so conceived and so dedicated (to the proposition that all men are created equal), can long endure."
Answering that test with a resounding YES was one of the most moral causes for which any war has ever been fought.
IMO of course.
The "institution" did not make them keep their own slaves. The point which you are continuously trying to skirt is that the principles asserted for them and their real world actions went in different directions.
The notion that the Founders did not think the principles of the DOI applied to Africans is the rationale behind the Dred Scott decision. It was conclusively refuted in the dissents to that atrocity, and many, many times since.
Dred Scott would not have been possible but for the obvious examples of the founders who created the Declaration continuing to keep slaves. It is irrational to believe that they would see the principles in the Declaration as encompassing slaves while they continued to keep them.
If they believed that the declaration applied to slaves, they would have immediately released all of theirs.
A classic example of projection. Secession and war by the South being about much of anything other than slavery was indeed an after-the-fact rationale to justify a war fought for an immoral cause.
For the sake of argument, let us assert that the south had the worst possible motives for wanting their independence. These motives have nothing to do with the North's motives for invading the South.
Again, the salient point which you are unwilling to face is that the North wasn't attempting to march down to Richmond Virginia to free any slaves. They just didn't. You are just lying to yourself if you believe that.
...Notably, the preliminary Emancipation Proclamation was issued 16 months after Sumter...
Over a year later? What had the Union troops been told in the meantime? What was their stated cause before he spent a year polishing his proclamation? Surely they had to have been told some reason for being sent to Richmond.
Also, as of August 22, 1862, Lincoln was saying that no freeing of slaves would also be acceptable to him. My friend, this is the smoking gun which puts the lie to your theory that the North invaded the South to destroy slavery.
They invaded to stop independence and then they "moved the goal posts."