That method of interpretation is call "textualism". It allows the person interpreting it to attribute to the words any one of a various meanings they might have, or come to have in modern lexicon. It makes no attempt to determine the original intent of the authors.
"On every question of construction, let us carry ourselves back to the time when the Constitution was adopted, recollect the spirit manifested in the debates, and instead of trying what meaning may be squeezed out of the text, or invented against it, conform to the probable one in which it was passed."
-Thomas Jefferson
I see no reason that should apply any less to any subsequent amendments than it does to the Constitution proper.
You can declare the "intent" of the authors irrelevant if you want. I won't follow you there, or anywhere else by that path.
In 1865, the meanings of the words “former slave,” “negro,” and “person” were precisely what they are today.
The authors of the amendment wrote “person.”
The “intent” I said was irrelevant was the supposed intent to protect the rights of ONLY former slaves or negroes. That may have been the primary purpose of the Fourteenth Amendment, but the word “person” was chosen, not “former slave” or “negro.”