I feel that when people read this kind of stories they immediately connect it to Trump, but the sad truth is that this is not something new and have been happening under previous administration too. The big difference is that previous administration didn't encourage it publicly, did not issue any executive orders for it, but that didn't stop border control from acting this way. The first thing you learn about US visa is that it doesn't guarantee US admission.
Don't take it as an attempt to downplay the issue, I just think that it's important to put it in the historical context as this behaviour isn't really new.
http://newsfeed.time.com/2012/01/31/british-tourists-tweets-... http://www.gadgetsnow.com/tech-news/us-deporting-valid-visa-... http://redbus2us.com/news-us-cbp-deports-14-students-many-st... http://www.telegraph.co.uk/travel/destinations/north-america...