He's speaking specifically about the green card process, at which point you've already been in the country for a long time and paid into U.S. taxes. Not people who might want to pay money to immigrate here (although for them, the EB-5 visa program exists).
I think the logic behind being anti-immigrant are "These people don't follow our culture" and "These people don't contribute to American society", then we should have objective criteria that addresses that. Time in U.S. is a proxy for acculturation; so measure that. And taxes paid is a direct financial measure of how much they have contributed to the American government. Both of these are extremely easy to ascertain from official records, so take the corruption and the human guesswork out of it and make clear and consistent rules that address the objectives you're trying to attain.
I think the logic behind being anti-immigrant are "These people don't follow our culture" and "These people don't contribute to American society", then we should have objective criteria that addresses that. Time in U.S. is a proxy for acculturation; so measure that. And taxes paid is a direct financial measure of how much they have contributed to the American government. Both of these are extremely easy to ascertain from official records, so take the corruption and the human guesswork out of it and make clear and consistent rules that address the objectives you're trying to attain.