I find this line of thinking so odd, because nobody ever says “exporting American {cars/corn/computers} to China drives up demand and costs to US citizens.” The worst-case scenario here is that education is economically just equivalent to an export, but that’s still a pretty great scenario! Especially since it’s an export that doesn’t pollute, supports high-paying labor, perpetuates the global premium associated with a US education, and has the side effect that sometimes foreign students do stay and continue to contribute to the economy.