The point is not whether immigrants can be heirs to the Founders (that's a separate debate). The point is that most Confederate haters didn't even have ancestors here then. The Yankees who actually fought them reconciled with them and grew to respect them. https://twitter.com/RadioFreeTom/status/1350200198744727552

The modern consensus is that the North should've exterminated the South's leadership caste, disenfranchised every Confederate vet, redistributed all property, and forced the South to endure a never-ending military occupation. Sensible northerners chose reconciliation instead

The reconciliation consensus lasted until basically the last 30 years or so. This is due to new arrivals deciding they’re the heirs of the Union army (they’re not) and wanting a second Reconstruction for all of Heritage America, not just the South