I'm sorry, but the the lack of rights has never meant they weren't citizens – any more than the lack of rights never meant that women were not citizens. In fact, that oppression of their rights is all the more heinous because the were birthright citizens. Moreover, no woman enjoyed the full rights of citizenship until Suffrage. To make your claim, you'd have to apply it to every person of African descent until at least the Civil Rights era. Your argument is flawed – it is legally and constitutionally unsound.

The Constitution itself does not mention slavery nor black and white people. But, the document guarantees birthright citizenship for all people born in the United States. The political compromise did not erase birthright citizenship of Black people – instead, it diminished them as humans and counted them legally 3/5ths of a citizen for political purposes. That is not the same thing as removing their constitutional birthright citizenship. Frankly, if you count their citizenship from when they had full access to citizen's rights, then African Americans and women would still not be citizens because neither of us have ever "enjoyed the full rights of citizenship."

I think you will find that no respected and qualified scholarship supports your flawed premise.