Politics is tribal. Everyone is offended by everything.
I voted to remain in the EU, but I was on the fence for a while. If I had voted to leave, I don’t think I would have been comfortable telling people; the level of discourse is now so low in this country that you get labelled EDL/racist within 2 minutes. Just look at the Brexit thread on here; everyone is a thick, gullible xenophobe who was tricked in to leaving.
There are people in the key swing states who will have moderate or left wing families, friends or colleagues, who might want to vote for Trump because they might be financially better off now than they were 5 years ago. They won’t be comfortable saying this though, because even though they know what their intentions are, they are fearful of being labelled a racist or xenophobe.
There is no reason to be a shy democrat, because the democrats, more so than the republicans, have a platform that is run partly on identity politics. No one is going to say ‘oh my god you voted democrat you are a racist’.
I don’t think most people are like this, but definitely 3-5% ish.