> From a geo political perspective, would you rather have these people working to build up US industry, or have them starting and staffing competition in their home countries?
This doesn't happen nearly as often as you probably think. Starting a company in many countries (including my birth country in Latin America) is very difficult. Not only there is no financing, but the justice system is also slow to resolve inevitable contract disputes. Additionally, government regulations crush advanced businesses to the point where it's really difficult for companies to compete internationally. The US remains one of the best places to start a tech company.
Given this, many smart people in my home country decide to work for the government in highly-paid paper-pushing roles, throwing away years of study and computer expertise.