Look, either citizenship is important or it's not. If you choose to think the US is a giant economic house party that can keep inviting in cool kids from around the world then you plainly don't care about citizenship. Fine, lead with that.
Myself, I think it DOES matter, even if most of us are US Citizens by birth. I vote, and pay taxes, and contribute to worthy causes in my community, and try to be a good American. Those other cool kids are likewise citizens of their birth countries, and they ought to be celebrating that and working to fix their own countries, not coming here because things are better economically.