of course their "founding ideals were false when they were written". Anyone who lives within a million miles of reality knows that they were false then and are largely false now. But then, so is the vanguard propaganda of nearly every revolution in modern history. And so are the conservatives who laughably try to deny it.
But one very quick and cursory look at https://en.wikipedia.org/wiki/The_1619_Project#August_14,_2019,_magazine_issue immediately reveals a wildly desperate attempt to morph our colorful history into an adamantly monochrome silhouette of oppressor and victim. The truth is way more complicated than that.