take a random sample of 100 devs in Ukraine and India and offer them a green card to the US of A. how many do you think would take it? and for people who wouldn't, how many do you think would cite Trump as their reason?
A better question is: take a random sample of 100 devs in Ukraine and India in early 2016 and offer them a green card, and then do the same today. How do the numbers compare? Now you're seeing how many people would have liked to come here, and now have changed their minds because of recent political events.