Ummm... https://arstechnica.com/tech-policy/2017/07/trump-begins-to-...

YC doesn't fund at $250k though. So that article isn't actually relevant to the concern over founders going to YC.

It's quite obvious that he's intend to reduce immigration. That's not likely an immediate problem for white founders from Europe. But there's obvious potential in Africa, the Middle East, or Asia. And it's crystal clear that if Trump gets his way, Elon Musk would have a rather hard time getting permanent residency in the US.

Apart from these actual, specific challenges, emigrating is a huge step for most people. The general hostility against "strangers" would definitely make me think twice about moving to the US today, even though I once spent a year in the Southwest and had a wonderful time.

Just dealing with customs officers at the airport has become a nightmare over the last decade: Being fingerprinted like a criminal is the most obvious change. But I've lately noticed that the attitude more and more resembles the thuggishness usually associated with police states. They have always had all the power, but lately they seem to relish to show it to you. Need 10 seconds to find your flight number? "Go to the back of the line, NOW, and try again with the respect the greatest country on the face of the earth deserves". (actual quote).

You get fingerprinted going into Europe too at some airports.

I'd be interested to know which European countries? And does it vary by the nationality of the visitor[1]?

[1] For the USA for example, Canadians visiting for business or tourism (an implied B1 or B2 visa, respectively), are exempt from fingerprinting. Canada is the only exception to the USA's fingerprinting rules.