How so? The idea of comparative advantage is that one country has a market, another, the means to provide for that market and you facilitate this 'trade'. India, China, pretty much most countries have plenty of top notch talent that cannot be satiated by opportunities within their own countries. These are not necessarily geniuses, but most high-performing highly skilled workers qualify. The satisfaction that these highly talented folks seek is often provided only in the US. For a moment, set aside the notion that people want to work in the US for greenbacks. This is only partially true, in my experience. Most friends and colleagues I know want to immigrate because their jobs are higher quality, as is the work culture, etc.
US provides the (job) market for top talent, China, India, Europe, etc. supply the talent.
Protectionism in this situation is just the act of putting ill-conceived roadblocks in this 'trade'. No one is asking for open borders, just a fair system where this 'trade' can be carried on smoothly.