I don't think this has any relation to Big Data. It's simply Trump supporters were clever enough to give out false signals due to being ostracized by media and

I don't think this has any relation to Big Data. It's simply Trump supporters were clever enough to give out false signals due to being ostracized by media and worried about consequences of going public (fired from a job, removed from social circles etc.) So the massive pressure on conformity created a late-Soviet-Union-style dissonance, outwardly many supporting "approved" candidates, inwardly supporting Trump (maybe due to the this pressure from all sides as a simple vote against). Many would've probably voted for "nobody" if that were a choice alongside Hillary and Donald.