Have you read through that link?

I'm not taking a side here, but it injects a couple more words that could imply something else:

[Mr. Howard] (Sen. from MI)

"This amendment which I have offered is simply declaratory as what I regard as the law of the land already, that every person born within the limits of the United States, and subject to their jurisdiction, is by virtue of natural law and national law a citizen of the United States.

This will not, of course, include persons born in the United States who are foreigners, aliens, who belong to the families of embassadors or foreign ministers accredited to the government of the United States, but will include every other class of persons.

It settles the great question of citizenship and removes all doubt as to what persons are or are not citizens of the United States."

(Apologies for any typos as this was hand written.)

What are the confusing words? You gave a quote that sums up the long-accepted understanding of who's exempt from the citizenship clause:

"This will not, of course, include persons born in the United States who are foreigners, aliens, who belong to the families of embassadors or foreign ministers accredited to the government of the United States, but will include every other class of persons."

They don't mention Indian tribes in that quote, but they mention it elsewhere. Seems completely clear to me.