The Constitution, as amended, says everyone must be counted.
It then also specifies that apportionment should be reduced by proportions of certain categories of non-qualifying people who are there.
For some reason, most of those arguing the first point, tend to leave out the second part of the same amendment.
The amendment says “their respective numbers” the invaders are not theirs and must not be counted.
Would you count the members of the Mexican army if Mexico officially declared war on us and occupied Arizona?
NO, you would not.
The civilian invaders are not different, they must not be counted and their children DO NOT receive citizenship just because they are born on US soil.