Baruch is the same way. Simply put, they seem to out-class the applicants from the US.
Quant finance requires a rigorous degree to enter, and connections. The top US colleges have that, but they are already based in the US and have better connections to US firms, and US firms recruit on their campuses. The top talent at the rigorous US colleges can often find a job out of undergrad, they don't need to go through the masters to prove themselves. Princeton has a major undergrad FE program and those students intern at 2sig and equivalents all the time.
The top colleges overseas are then the highest caliber students available, but they have much fewer connections in the US. Transferring to a finance position across the pond is notoriously difficult. This leads the top talent to apply to masters programs here in the US so they can make connections, acquire a US based degree, and get an inroad to jobs through the masters program staff and alumni.
It's not that US students can't do it, they are doing it, and the best ones don't need a masters program to do it. That leaves the comparatively lesser US talent to compete with the top overseas talent, and the students from Peking, Lisang (butchered that one, I think, please forgive me), and the Indian IIT's usually win.
This is a large part of why I'm studying abroad, so I can take a couple courses as an undergraduate that my college doesn't even teach graduate students. I need some more rigor to compete. I'm not at a top school, we are 'tier 2' (around 70 in US news and world report, for what that is worth, which isn't terribly much but its better than nothing.