I don't know what pedantic definition you're using, but the context was clearly about indigenous or not. Insisting on a definition from a completely different context doesn't make you right, it makes you annoying.
It shouldn't be annoying when somebody politely and indirectly asks you to stop calling kidnapped slaves "immigrants."
I see what you're saying, however, the terminology used (immigrant) and then percentages given, were debatably incorrect and misleading. Please refer to reading material, where it makes it clear that slavery is not immigration[1][2][3].
Immigrants go through a set immigration process, where they make a voluntary move to a new country. A huge portion of the American population were not immigrants, but were rather subject to involuntary migration (aka slavery), going as far back as 1526 (hundreds of years before the USA was created). Thus a better term would arguably be "migrants" (without distinguishing between voluntary and involuntary).
> And that is what binds them together... they all seperated from the old world... The us is a phyle of choice and you must have made that choice...
It is a false dichotomy or representation, that America is about those who are indigenous or not, or old world choice for the new.
[1]: https://lithub.com/dont-call-slaves-immigrants/ (Don't Call Slaves "Immigrants")
[2]: https://www.thewitnessinc.org/blog/african-slaves-not-immigr... (African Slaves Were Not 'Immigrants')
[3]: https://www.washingtonpost.com/posteverything/wp/2017/03/09/... (Slaves weren’t immigrants. They were property.)