The Article clearly states their intent, which was to count the "whole number of free persons." Every free person living in a state was to be counted.
Then they delineated their exceptions:.
Slaves as 3/5 of a "whole" person
Indians (not taxed) because they were never intended to be part of the new nation. That is why they weren't taxed.
If they had wanted to exclude non-citizens they would have done so. You are putting your words in their pens. You are desperate to change the original intent. The country wanted to grow and prosper and all were welcome.