I think the question we may be grappling with here is how do we hold on to the right ideals of the founding and Constitution, and I believe they were right, yet reconcile that with the historical record where we fell short of those ideals?
I am fairly well versed in US history, including the stains on our record. I have also developed over time an appreciation for understanding historical figures and events in their own time and not applying present circumstances to the past. Our American forebears grappled with difficult issues and had to make choices reflecting the reality of their time.
You mention Thomas Jefferson’s concern about Divine retribution for the incorporation of slavery in the founding of the United States. There was already a strong abolitionist movement at the time. In the original version of the Declaration of Independence, Jefferson spent an entire paragraph decrying the evils of slavery. So why wasn’t that paragraph in the final document? They knew if the rebellion had a chance of being successful the colonies would all have to stick together. The Declaration had to be passed unanimously. If some peeled off and remained loyal to the British, the entire endeavor would fail. The only way the Southern colonies would come along was if they did not take a strong anti-slavery position. Therefore, the horrible compromise was made. And it was a horror.
Similarly with ratification of the Constitution, the 3/5 compromise was made with the Southern States. It was a compromise because neither side got everything they wanted. The South wanted slaves to count fully in the apportionment of seats in the House, yet without giving the slaves the right to vote. The abolitionists in the North insisted they should not be counted at all, unless given the vote. Yet a compromise was reached to ratify the Constitution.
At the time of the Constitutional Convention, the fledgling country was on the brink and it was clear to all the original organization of the nation under the Articles of Confederation was insufficient. It was not perfect, but viewed through the perspective of the time, I would argue ratifying the Constitution imperfectly was a better alternative than allowing the United States to dissolve.
Similarly, you mentioned that only land owners were given the right to vote in the early days of the United States. True, but why? Was it because the landed gentry wanted to oppress the sharecroppers and renters? No, it is not exactly that simple. There was a great debate over enfranchisement centered on how to balance the rights of the two groups. According to the Library of Congress, Madison described the issue stating, “the right of suffrage is a fundamental Article in Republican Constitutions. The regulation of it is, at the same time, a task of peculiar delicacy. Allow the right [to vote] exclusively to property [owners], and the rights of persons may be oppressed… . Extend it equally to all, and the rights of property [owners] …may be overruled by a majority without property…”. In other words, the concern was that landless voters could pass measures beneficial to themselves at the expense of the landowner. In the end, the framers actually left the issue of suffrage to the states. Many states quickly expanded the right to vote to all adult white males or even women who were head of household.
You can make a similar analysis of all of the difficult issues faced by the early Americans. Would it have been better for Jefferson and the other Founders who realized the evil of slavery to stand on principle and allow the fledgling rebellion to end? We can never know, however, I would argue that with the United States leading the western world, we have seen the greatest advancements for the betterment of humanity in the shortest period of time in recorded history. It led to an economic system that has produced more advancements and lifted more people worldwide out of abject poverty than at any other time. I believe the success of our nation was in large part because of the guiding principles of the founders as expressed in the Constitution.
I would caution that we should not throw out or discount those guiding principles because of the shortcomings of prior generations. Just because they fell short does not mean the values were incorrect. Rather we understand why compromises were made in the past appreciating history in its context. We learn from the mistakes and work to better realize the American promise. Ideas do matter.