Slaughter House referred to the language of the initial Civil right act that stated
"All persons born in the United States, and not subject to any foreign power, excluding Indians not taxed, are hereby declared to be citizens of the United States."
There is not one word as to the political status of the parents, whether diplomat or not, Period. WKA did not overturn A2S1C5. In order for your illogical statement to even have a hint of truth, A2S1C5 would have had to have been amended and thus far, not such amendment language language is attached to it, nor does any other amendment, 14th included, refer to A2S1C5.
The fact is, prior to emancipation, slaves held political allegiance to no body but they did owe complete obedience to their master, thus they were under the political jurisdiction of the master. when they became free slaves who had been born with no political allegiance, they "naturally" became members of the society in which they lived if they so chose. Citizenship was never forced upon them and to my knowledge & research thus far, not one slave upon being freed was ordered to swear an oath of allegiance. Now if you can find me the language of a federal law that required them to do so, then you have an sound argument that the 14th was a naturalization act, but until it is produced, the freed slaves gained citizenship via the fact that they were born on US soil and did not owe allegiance to a foreign nation at birth.
You should have kept reading. But if you prefer ignorance, go ahead. WKA overturned a part of Slaughterhouse:
“The phrase, “subject to its jurisdiction” was intended to exclude from its operation children of ministers, consuls, and citizens or subjects of foreign States born within the United States.
This was wholly aside from the question in judgment and from the course of reasoning bearing upon that question. It was unsupported by any argument, or by any reference to authorities, and that it was not formulated with the same care and exactness as if the case before the court had called for an exact definition of the phrase...”